Make it clearer that sc_wdc_bio.blkno is actuall a disk hardware address by using the DL_BLKTOSEC() and DL_SECTOBLK() defines rather than handrolling the equivalent. Fixes current addition of a 512-byte block value (b_blkno) to a disk hardware address (DL_GETPOFFSET()).
Make it clearer that sc_wdc_bio.blkno is actuall a disk hardware
address by using the DL_BLKTOSEC() and DL_SECTOBLK() defines rather
than handrolling the equivalent. Fixes current addition of a 512-byte
block value (b_blkno) to a disk hardware address (DL_GETPOFFSET()).

Tested on real wd(4) hardware by guenther@.

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