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>