btrfs: remove support of balance v1 ioctl

It was scheduled for removal in kernel v5.18 commit 6c405b24
("btrfs: deprecate BTRFS_IOC_BALANCE ioctl") thus its time has come.
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ioctl.c

@@ -5456,8 +5456,6 @@ long btrfs_ioctl(struct file *file, unsigned int
 		return btrfs_ioctl_fs_info(fs_info, argp);
 	case BTRFS_IOC_DEV_INFO:
 		return btrfs_ioctl_dev_info(fs_info, argp);
-	case BTRFS_IOC_BALANCE:
-		return btrfs_ioctl_balance(file, NULL);
 	case BTRFS_IOC_TREE_SEARCH:
 		return btrfs_ioctl_tree_search(inode, argp);
 	case BTRFS_IOC_TREE_SEARCH_V2: