Now that all callers are using the _nr variations we can simply rename
these helpers to btrfs_item_##member/btrfs_set_item_##member and change
the actual item SETGET funcs to raw_item_##member/set_raw_item_##member
and then change all callers to drop the _nr part.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>