SDEV_UMASS devices skip the mode page dance to set blksize. So initialize blksize to 0 to avoid confusing garbage values with useful info.
SDEV_UMASS devices skip the mode page dance to set blksize. So initialize
blksize to 0 to avoid confusing garbage values with useful info.

Noticed by jolan@.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars