sata_mv: remove unnecessary initialization

sata_mv initializes unused ioports fields including bmdma_addr to
NULL.  As later changes will conditionalize BMDMA, this makes sata_mv
unnecessarily dependent on BMDMA.  Remove the unnecessary
initialization.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>