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>
diff --git a/hw/block/swim.c b/hw/block/swim.c
index 8f12478..74f56e8 100644
--- a/hw/block/swim.c
+++ b/hw/block/swim.c
@@ -189,7 +189,10 @@
         assert(ret == 0);
     }
 
-    blkconf_blocksizes(&dev->conf);
+    if (!blkconf_blocksizes(&dev->conf, errp)) {
+        return;
+    }
+
     if (dev->conf.logical_block_size != 512 ||
         dev->conf.physical_block_size != 512)
     {