Added format flags to lfsr_format

This is mainly to solve the weird check-hole where passing CKPROGS/
CKREADS as mount flags has no effect on lfsr_format (I mean, it'd be a
bit silly if it did somehow):

  LFS_F_RDWR              0  // Format the filesystem as read and write
  LFS_F_CKPROGS  0x00000010  // Check progs by reading back progged data
  LFS_F_CKREADS  0x00000020  // Check reads via parity bits/checksums

This makes lfsr_format a more cumbersome interface, but I don't know if
this is necessarily a bad thing. There's always risk of data loss when
calling lfsr_format, so maybe it should be a pain to call.

At the very least, format flags may be useful in the future for
enabling/disabling format-time things such as the planned block-map,
parity-tree, etc. Though it's unclear if such significant settings
should be format flags or somehow encoded as fields in our config
struct.

---

The LFS_F_* format flags of course ended up conflicting with our
internal LFS_F_* flags, so I renamed most of the internal flags to match
the closest flag set they participate in:

- LFS_F_TYPE        -> LFS_O_TYPE
- LFS_F_UNFLUSH     -> LFS_O_UNFLUSH
- LFS_F_UNSYNC      -> LFS_O_UNSYNC
- LFS_F_ORPHAN      -> LFS_O_ORPHAN
- LFS_F_ZOMBIE      -> LFS_O_ZOMBIE

- LFS_F_ORPHANS     -> LFS_I_ORPHANS
- LFS_F_UNCOMPACTED -> LFS_I_UNCOMPACTED

- LFS_F_TSTATE      -> LFS_T_TSTATE
- LFS_F_BTYPE       -> LFS_T_BTYPE
- LFS_F_DIRTY       -> LFS_T_DIRTY
- LFS_F_MUTATED     -> LFS_T_MUTATED

This may make it a bit less clear which flags are a part of the public
API, vs intended only for internal use, but at the very least our asserts
in format/mount/open/etc should catch most of these mistakes.

---

Code cost ended up being pretty minimal. Actually negative. This is the
second time we're _adding_ a feature that somehow saves code, though the
reality for this one is we're really just pushing constants up into the
user's stack frame. Still, it's a good indication the cost of format
flags is small:

           code          stack
  before: 36452           2680
  after:  36448 (-0.0%)   2680 (+0.0%)

tests/test_alloc.toml

@@ -26,7 +26,7 @@ code = '''
     struct lfs_config cfg = *CFG;
     cfg.block_count = COUNT;
     lfs_t lfs;
-    lfsr_format(&lfs, &cfg) => 0;
+    lfsr_format(&lfs, LFS_F_RDWR, &cfg) => 0;
     lfsr_mount(&lfs, LFS_M_RDWR, &cfg) => 0;
 
     // start allocating
@@ -70,7 +70,7 @@ code = '''
     struct lfs_config cfg = *CFG;
     cfg.block_count = COUNT;
     lfs_t lfs;
-    lfsr_format(&lfs, &cfg) => 0;
+    lfsr_format(&lfs, LFS_F_RDWR, &cfg) => 0;
     lfsr_mount(&lfs, LFS_M_RDWR, &cfg) => 0;
 
     // start allocating
@@ -127,7 +127,7 @@ defines.REMOUNT = [false, true]
 in = 'lfs.c'
 code = '''
     lfs_t lfs;
-    lfsr_format(&lfs, CFG) => 0;
+    lfsr_format(&lfs, LFS_F_RDWR, CFG) => 0;
     lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
 
     // create this many directories
@@ -292,7 +292,7 @@ in = 'lfs.c'
 if = '(SIZE*N)/BLOCK_SIZE <= 32'
 code = '''
     lfs_t lfs;
-    lfsr_format(&lfs, CFG) => 0;
+    lfsr_format(&lfs, LFS_F_RDWR, CFG) => 0;
     lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
 
     // create this many files
@@ -465,7 +465,7 @@ in = 'lfs.c'
 if = '(SIZE*N)/BLOCK_SIZE <= 32'
 code = '''
     lfs_t lfs;
-    lfsr_format(&lfs, CFG) => 0;
+    lfsr_format(&lfs, LFS_F_RDWR, CFG) => 0;
     lfsr_mount(&lfs, LFS_M_RDWR, CFG) => 0;
 
     // create this many files
@@ -644,7 +644,7 @@ code = '''
     struct lfs_config cfg = *CFG;
     cfg.block_count = COUNT;
     lfs_t lfs;
-    lfsr_format(&lfs, &cfg) => 0;
+    lfsr_format(&lfs, LFS_F_RDWR, &cfg) => 0;
     lfsr_mount(&lfs, LFS_M_RDWR, &cfg) => 0;
 
     // create directories until we run out of space
@@ -726,7 +726,7 @@ code = '''
     struct lfs_config cfg = *CFG;
     cfg.block_count = COUNT;
     lfs_t lfs;
-    lfsr_format(&lfs, &cfg) => 0;
+    lfsr_format(&lfs, LFS_F_RDWR, &cfg) => 0;
     lfsr_mount(&lfs, LFS_M_RDWR, &cfg) => 0;
 
     // create files until we run out of space