Fixed implicit change-of-sign warning in lfs_dir_fetch

Warning on MDK v5.27.1
Found by geniusgogo

lfs.c

@@ -975,9 +975,10 @@ static lfs_stag_t lfs_dir_fetchmatch(lfs_t *lfs,
 
 static int lfs_dir_fetch(lfs_t *lfs,
         lfs_mdir_t *dir, const lfs_block_t pair[2]) {
-    // note, mask=-1, tag=0 can never match a tag since this
+    // note, mask=-1, tag=-1 can never match a tag since this
     // pattern has the invalid bit set
-    return (int)lfs_dir_fetchmatch(lfs, dir, pair, -1, 0, NULL, NULL, NULL);
+    return (int)lfs_dir_fetchmatch(lfs, dir, pair,
+            (lfs_tag_t)-1, (lfs_tag_t)-1, NULL, NULL, NULL);
 }
 
 static int lfs_dir_getgstate(lfs_t *lfs, const lfs_mdir_t *dir,
@@ -1643,7 +1644,6 @@ relocate:
         if (err && (err != LFS_ERR_NOSPC && !exhausted)) {
             return err;
         }
-
         continue;
     }
 
@@ -4614,7 +4614,7 @@ int lfs_migrate(lfs_t *lfs, const struct lfs_config *cfg) {
                             id, entry1.d.nlen), name},
                         {LFS_MKTAG(
                             isdir ? LFS_TYPE_DIRSTRUCT : LFS_TYPE_CTZSTRUCT,
-                            id, sizeof(entry1.d.u)), &entry1.d.u}));
+                            id, sizeof(&entry1.d.u)), &entry1.d.u}));
                 lfs1_entry_fromle32(&entry1.d);
                 if (err) {
                     goto cleanup;
@@ -4637,7 +4637,7 @@ int lfs_migrate(lfs_t *lfs, const struct lfs_config *cfg) {
 
                 lfs_pair_tole32(dir2.pair);
                 err = lfs_dir_commit(lfs, &dir2, LFS_MKATTRS(
-                        {LFS_MKTAG(LFS_TYPE_SOFTTAIL, 0x3ff, 8),
+                        {LFS_MKTAG(LFS_TYPE_SOFTTAIL, 0x3ff, 0),
                             dir1.d.tail}));
                 lfs_pair_fromle32(dir2.pair);
                 if (err) {