[libata] sata_mv: fix oops by filling in missing hook

Only two of three ata_port_operations structs had a ->data_xfer member,
which led to, uh, a lack of data xfer.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index fdce6e0..c01496d 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -463,6 +463,7 @@
 
 	.qc_prep		= mv_qc_prep_iie,
 	.qc_issue		= mv_qc_issue,
+	.data_xfer		= ata_mmio_data_xfer,
 
 	.eng_timeout		= mv_eng_timeout,