[PATCH] libata: flush COMRESET set and clear

Updated patch to fix erroneous flush of COMRESET set and missing flush
of COMRESET clear.  Created a new routine scr_write_flush() to try to
prevent this in the future.  Also, this patch is based on libata-2.6
instead of the previous libata-dev-2.6 based patch.

Signed-off-by: Brett Russ <russb@emc.com>

Index: libata-2.6/drivers/scsi/libata-core.c
===================================================================
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index f70935c..ee9b96d 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1253,11 +1253,11 @@
 	unsigned long timeout = jiffies + (HZ * 5);
 
 	if (ap->flags & ATA_FLAG_SATA_RESET) {
-		scr_write(ap, SCR_CONTROL, 0x301); /* issue phy wake/reset */
-		scr_read(ap, SCR_STATUS);	/* dummy read; flush */
+		/* issue phy wake/reset */
+		scr_write_flush(ap, SCR_CONTROL, 0x301);
 		udelay(400);			/* FIXME: a guess */
 	}
-	scr_write(ap, SCR_CONTROL, 0x300);	/* issue phy wake/clear reset */
+	scr_write_flush(ap, SCR_CONTROL, 0x300); /* phy wake/clear reset */
 
 	/* wait for phy to become ready, if necessary */
 	do {