Some minor grm tweaks

- Dropped lfsr_grm_hasrm

- Switched to >=0 for lfsr_grm_count, this should optimize to just
  adding sign bits together

- Changed lfsr_grm_pop to return popped mid

- Renamed lfsr_grm_ispending -> lfsr_grm_ismidrm

- Added assert on malformed grm {-1, >=0}, this shouldn't happen

Code changes:

           code          stack
  before: 34470           2624
  after:  34478 (+0.0%)   2624 (+0.0%)

lfs.c

@@ -5571,12 +5571,8 @@ static inline void lfsr_gdelta_xor(
 
 
 // grm (global remove) things
-static inline bool lfsr_grm_hasrm(const lfsr_grm_t *grm) {
-    return grm->mids[0] != -1;
-}
-
 static inline uint8_t lfsr_grm_count(const lfsr_grm_t *grm) {
-    return (grm->mids[0] != -1) + (grm->mids[1] != -1);
+    return (grm->mids[0] >= 0) + (grm->mids[1] >= 0);
 }
 
 static inline void lfsr_grm_push(lfsr_grm_t *grm, lfsr_smid_t mid) {
@@ -5585,12 +5581,14 @@ static inline void lfsr_grm_push(lfsr_grm_t *grm, lfsr_smid_t mid) {
     grm->mids[0] = mid;
 }
 
-static inline void lfsr_grm_pop(lfsr_grm_t *grm) {
+static inline lfsr_smid_t lfsr_grm_pop(lfsr_grm_t *grm) {
+    lfsr_smid_t mid = grm->mids[0];
     grm->mids[0] = grm->mids[1];
     grm->mids[1] = -1;
+    return mid;
 }
 
-static inline bool lfsr_grm_ispending(const lfsr_grm_t *grm,
+static inline bool lfsr_grm_ismidrm(const lfsr_grm_t *grm,
         lfsr_smid_t mid) {
     return grm->mids[0] == mid || grm->mids[1] == mid;
 }
@@ -5877,7 +5875,7 @@ static int lfsr_mdir_lookupnext(lfs_t *lfs, const lfsr_mdir_t *mdir,
     // semantics, and it's easier to manage the implied mid gap in
     // higher-levels
     if (lfsr_tag_suptype(tag__) == LFSR_TAG_NAME
-            && lfsr_grm_ispending(&lfs->grm, mdir->mid)) {
+            && lfsr_grm_ismidrm(&lfs->grm, mdir->mid)) {
         tag__ = LFSR_TAG_ORPHAN;
     }
 
@@ -7516,7 +7514,7 @@ static int lfsr_mdir_namelookup(lfs_t *lfs, const lfsr_mdir_t *mdir,
     // fortunately pending grms/orphaned files have roughly the same
     // semantics, and it's easier to manage the implied mid gap in
     // higher-levels
-    if (lfsr_grm_ispending(&lfs->grm, mid)) {
+    if (lfsr_grm_ismidrm(&lfs->grm, mid)) {
         tag = LFSR_TAG_ORPHAN;
     }
 
@@ -8824,11 +8822,9 @@ static int lfsr_mountinited(lfs_t *lfs) {
         return err;
     }
 
-    if (lfsr_grm_hasrm(&lfs->grm)) {
     // found pending grms? this should only happen if we lost power
     if (lfsr_grm_count(&lfs->grm) == 2) {
-            LFS_DEBUG("Found pending grm "
+        LFS_DEBUG("Found pending grm %"PRId32".%"PRId32" %"PRId32".%"PRId32,
-                    "%"PRId32".%"PRId32" %"PRId32".%"PRId32,
                 lfsr_mid_bid(lfs, lfs->grm.mids[0]) >> lfs->mdir_bits,
                 lfsr_mid_rid(lfs, lfs->grm.mids[0]),
                 lfsr_mid_bid(lfs, lfs->grm.mids[1]) >> lfs->mdir_bits,
@@ -8838,7 +8834,6 @@ static int lfsr_mountinited(lfs_t *lfs) {
                 lfsr_mid_bid(lfs, lfs->grm.mids[0]) >> lfs->mdir_bits,
                 lfsr_mid_rid(lfs, lfs->grm.mids[0]));
     }
-    }
 
     return 0;
 }
@@ -9185,7 +9180,9 @@ lfs_ssize_t lfsr_fs_size(lfs_t *lfs) {
 // consistency stuff
 
 static int lfsr_fs_fixgrm(lfs_t *lfs) {
-    while (lfsr_grm_hasrm(&lfs->grm)) {
+    while (lfsr_grm_count(&lfs->grm) > 0) {
+        LFS_ASSERT(lfs->grm.mids[0] != -1);
+
         // find our mdir
         lfsr_mdir_t mdir;
         int err = lfsr_mtree_lookup(lfs, lfs->grm.mids[0],
@@ -9267,10 +9264,9 @@ static int lfsr_fs_fixorphans(lfs_t *lfs) {
 int lfsr_fs_mkconsistent(lfs_t *lfs) {
     // fix pending grms
     bool wasinconsistent = false;
-    if (lfsr_grm_hasrm(&lfs->grm)) {
+    if (lfsr_grm_count(&lfs->grm) > 0) {
         if (lfsr_grm_count(&lfs->grm) == 2) {
-            LFS_DEBUG("Fixing grm "
+            LFS_DEBUG("Fixing grm %"PRId32".%"PRId32" %"PRId32".%"PRId32,
-                    "%"PRId32".%"PRId32" %"PRId32".%"PRId32"...",
                     lfsr_mid_bid(lfs, lfs->grm.mids[0]) >> lfs->mdir_bits,
                     lfsr_mid_rid(lfs, lfs->grm.mids[0]),
                     lfsr_mid_bid(lfs, lfs->grm.mids[1]) >> lfs->mdir_bits,