Revert "power_state: get rid of write-only variable in SATA"

This reverts commit 559bbe6c.

Michael S. Tsirkin reports that this changes breaks suspend/resume.
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

drivers/ata/libata-core.c

@@ -6567,6 +6567,8 @@ int ata_host_suspend(struct ata_host *host, pm_message_t mesg)
 	ata_lpm_enable(host);
 
 	rc = ata_host_request_pm(host, mesg, 0, ATA_EHI_QUIET, 1);
+	if (rc == 0)
+		host->dev->power.power_state = mesg;
 	return rc;
 }
 
@@ -6585,6 +6587,7 @@ void ata_host_resume(struct ata_host *host)
 {
 	ata_host_request_pm(host, PMSG_ON, ATA_EH_SOFTRESET,
 			    ATA_EHI_NO_AUTOPSY | ATA_EHI_QUIET, 0);
+	host->dev->power.power_state = PMSG_ON;
 
 	/* reenable link pm */
 	ata_lpm_disable(host);