[SCSI] megaraid: outb_p extermination

From conversations with the maintainers the _p isn't needed so kill it.
That removes the last non ISA _p user from the SCSI layer to my knowledge.

Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: "Yang, Bo" <Bo.Yang@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>