block: consolidate blocksize properties consistency checks

block: consolidate blocksize properties consistency checks

Several block device properties related to blocksize configuration must
be in certain relationship WRT each other: physical block must be no
smaller than logical block; min_io_size, opt_io_size, and
discard_granularity must be a multiple of a logical block.

To ensure these requirements are met, add corresponding consistency
checks to blkconf_blocksizes, adjusting its signature to communicate
possible error to the caller.  Also remove the now redundant consistency
checks from the specific devices.

Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-Id: <20200528225516.1676602-3-rvkagan@yandex-team.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>