uapi: linux/blkzoned.h: fix BLKGETZONESZ and BLKGETNRZONES definitions

According to the documentation in include/uapi/asm-generic/ioctl.h,
_IOW means userspace is writing and kernel is reading, and
_IOR means userspace is reading and kernel is writing.

In case of these two ioctls, kernel is writing and userspace is reading,
so they have to be _IOR instead of _IOW.

Fixes: 72cd8757 ("block: Introduce BLKGETZONESZ ioctl")
Fixes: 65e4e3ee ("block: Introduce BLKGETNRZONES ioctl")
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>