Doc: f2fs: Fix typo in Documentation/filesystems/f2fs.txt

This patch fix a typo in f2fs.txt
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

Documentation/filesystems/f2fs.txt

@@ -131,7 +131,7 @@ inline_dentry          Enable the inline dir feature: data in new created
                        directory entries can be written into inode block. The
                        space of inode block which is used to store inline
                        dentries is limited to ~3.4k.
-noinline_dentry        Diable the inline dentry feature.
+noinline_dentry        Disable the inline dentry feature.
 flush_merge	       Merge concurrent cache_flush commands as much as possible
                        to eliminate redundant command issues. If the underlying
 		       device handles the cache_flush command relatively slowly,