ata: libata-core: Do not poweroff runtime suspended ports

When powering off, there is no need to suspend a port that has already
been runtime suspended. Skip the EH PM request in ata_port_pm_poweroff()
in this case.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/ata/libata-core.c

@@ -5215,7 +5215,8 @@ static int ata_port_pm_freeze(struct device *dev)
 
 static int ata_port_pm_poweroff(struct device *dev)
 {
-	ata_port_suspend(to_ata_port(dev), PMSG_HIBERNATE, false);
+	if (!pm_runtime_suspended(dev))
+		ata_port_suspend(to_ata_port(dev), PMSG_HIBERNATE, false);
 	return 0;
 }