[SCSI] a100u2w: fix bitmap lookup routine

This patch is only compile tested.

It seems that bitmap lookup routine for allocation_map in
a100u2w driver is simply wrong.

It cannot lookup more than first 32 bits. If all first 32 bits
are set, it just returns 33-th orc_scb even though the 33-th bit
is not set.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Tested-by: Alan Cox <alan@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>