ata: ahci_platform: add support for AHCI controller regulator

The SoC R40 AHCI controller need a regulator to work.
So this patch add a way to add an optional regulator on AHCI controller.

Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 6a1515f..1415f10 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -352,6 +352,7 @@ struct ahci_host_priv {
 	struct clk		*clks[AHCI_MAX_CLKS]; /* Optional */
 	struct reset_control	*rsts;		/* Optional */
 	struct regulator	**target_pwrs;	/* Optional */
+	struct regulator	*ahci_regulator;/* Optional */
 	/*
 	 * If platform uses PHYs. There is a 1:1 relation between the port number and
 	 * the PHY position in this array.