mfi_despatch_cmd() func after merging changes in rev 1.12.
Merge rev 1.69 and 1.64 from openbsd, fixing two bugs:
Fix subtle x ? y : z bug when calling mfi_create_sgl. This worked because
during runtime the bug condition does not happen.
When determining the size of the volumes and disks we want how many
bytes each of them has, not the number of kilobytes. this solves the
"why am i dividing by 2" question. the answer is "you dont, you multiply
by 512".
The first item fixes a panic with Dell Perc 5/i reported by oster@.
Changes tested on Dell Perc 5/i by oster@.