[PATCH] libata: add dev->ap

Add dev->ap which points back to the port the device belongs to.  This
makes it unnecessary to pass @ap for silly reasons (e.g. printks).
Also, this change is necessary to accomodate later PM support which
will introduce ATA link inbetween port and device.

Signed-off-by: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 56f0af2..31b65e0 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -4749,6 +4749,7 @@
 
 	for (i = 0; i < ATA_MAX_DEVICES; i++) {
 		struct ata_device *dev = &ap->device[i];
+		dev->ap = ap;
 		dev->devno = i;
 		dev->pio_mask = UINT_MAX;
 		dev->mwdma_mask = UINT_MAX;