fat: use fat_detach() in fat_clear_inode()

Use fat_detach() instead of opencoding it.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/fat/inode.c

@@ -429,13 +429,8 @@ static void fat_delete_inode(struct inode *inode)
 
 static void fat_clear_inode(struct inode *inode)
 {
-	struct super_block *sb = inode->i_sb;
-	struct msdos_sb_info *sbi = MSDOS_SB(sb);
-
-	spin_lock(&sbi->inode_hash_lock);
 	fat_cache_inval_inode(inode);
-	hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
-	spin_unlock(&sbi->inode_hash_lock);
+	fat_detach(inode);
 }
 
 static void fat_write_super(struct super_block *sb)