dm table: add more context to terse warning messages

A couple of recent warning messages make it difficult for the reader to
determine exactly what is wrong.  This patch adds more information to
those messages.

The messages were added by these commits:
  5dea271b ("dm table: pass correct dev area size
to device_area_is_valid")
  ea9df47c

 ("dm table: fix blk_stack_limits arg
to use bytes not sectors")

The patch also corrects references to logical_block_size in printk format
strings from %hu to %u.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>