btrfs: remove redundant null check in btrfs_dentry_release()

It doesn't need to check NULL for kfree()
Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>

fs/btrfs/inode.c

@@ -5168,8 +5168,7 @@ static int btrfs_dentry_delete(const struct dentry *dentry)
 
 static void btrfs_dentry_release(struct dentry *dentry)
 {
-	if (dentry->d_fsdata)
-		kfree(dentry->d_fsdata);
+	kfree(dentry->d_fsdata);
 }
 
 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,