[SCSI] advansys: Move a couple of fields from struct board to struct adv_dvc

board->carrp is a duplicate of asc_dvc->carrier_buf, so cut out the
middle-man and assign directly to carrier_buf.  Move orig_reqp to adv_dvc
too, since it's wide-board specific.  Also eliminate an unnecessary BUG_ON
(we'll never get there with a NULL carrier_buf, and will crash if we do).
The bulk of this patch is rearranging structures so everything's declared
in the right order.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>