Deduplicate lfsr_fs_ckmeta/data -> lfsr_fs_ck internally

This just saves a bit of code:

           code          stack
  before: 36424           2664
  after:  36356 (-0.2%)   2664 (+0.0%)

lfs.c

@@ -13000,40 +13000,30 @@ int lfsr_fs_mkconsistent(lfs_t *lfs) {
     return 0;
 }
 
-// check the filesystem for metadata errors
+// filesystem check functions
+static int lfsr_fs_ck(lfs_t *lfs, uint32_t flags) {
+    // we leave this up to lfsr_mtree_traverse
+    lfsr_traversal_t t = LFSR_TRAVERSAL(flags);
+    while (true) {
+        int err = lfsr_mtree_traverse(lfs, &t,
+                NULL, NULL);
+        if (err) {
+            if (err == LFS_ERR_NOENT) {
+                break;
+            }
+            return err;
+        }
+    }
+
+    return 0;
+}
+
 int lfsr_fs_ckmeta(lfs_t *lfs) {
-    // we leave this up to lfsr_mtree_traverse
+    return lfsr_fs_ck(lfs, LFS_T_CKMETA);
-    lfsr_traversal_t t = LFSR_TRAVERSAL(LFS_T_CKMETA);
-    while (true) {
-        int err = lfsr_mtree_traverse(lfs, &t,
-                NULL, NULL);
-        if (err) {
-            if (err == LFS_ERR_NOENT) {
-                break;
-            }
-            return err;
-        }
 }
 
-    return 0;
-}
-
-// check the filesystem for metadata + data errors
 int lfsr_fs_ckdata(lfs_t *lfs) {
-    // we leave this up to lfsr_mtree_traverse
+    return lfsr_fs_ck(lfs, LFS_T_CKMETA | LFS_T_CKDATA);
-    lfsr_traversal_t t = LFSR_TRAVERSAL(LFS_T_CKMETA | LFS_T_CKDATA);
-    while (true) {
-        int err = lfsr_mtree_traverse(lfs, &t,
-                NULL, NULL);
-        if (err) {
-            if (err == LFS_ERR_NOENT) {
-                break;
-            }
-            return err;
-        }
-    }
-
-    return 0;
 }
 
 // perform any pending janitorial work