btrfs: remove super block argument from btrfs_iget_locked()

It's pointless to pass a super block argument to btrfs_iget_locked()
because we always pass a root and from it we can get the super block
through:

   root->fs_info->sb

So remove the super block argument.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -5573,8 +5573,7 @@ static int btrfs_find_actor(struct inode *inode, void *opaque)
 		args->root == BTRFS_I(inode)->root;
 }
 
-static struct inode *btrfs_iget_locked(struct super_block *s, u64 ino,
-				       struct btrfs_root *root)
+static struct inode *btrfs_iget_locked(u64 ino, struct btrfs_root *root)
 {
 	struct inode *inode;
 	struct btrfs_iget_args args;
@@ -5583,7 +5582,7 @@ static struct inode *btrfs_iget_locked(struct super_block *s, u64 ino,
 	args.ino = ino;
 	args.root = root;
 
-	inode = iget5_locked(s, hashval, btrfs_find_actor,
+	inode = iget5_locked(root->fs_info->sb, hashval, btrfs_find_actor,
 			     btrfs_init_locked_inode,
 			     (void *)&args);
 	return inode;
@@ -5601,7 +5600,7 @@ struct inode *btrfs_iget_path(u64 ino, struct btrfs_root *root,
 	struct inode *inode;
 	int ret;
 
-	inode = btrfs_iget_locked(root->fs_info->sb, ino, root);
+	inode = btrfs_iget_locked(ino, root);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);