usb: dwc2: simplify optional reset handling

As of commit bb475230b8e5 ("reset: make optional functions really
optional"), the reset framework API calls use NULL pointers to describe
optional, non-present reset controls.

This allows to return errors from devm_reset_control_get_optional and to
call reset_control_(de)assert unconditionally.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc2/platform.c

@@ -214,20 +214,11 @@ static int dwc2_lowlevel_hw_init(struct dwc2_hsotg *hsotg)
 	hsotg->reset = devm_reset_control_get_optional(hsotg->dev, "dwc2");
 	if (IS_ERR(hsotg->reset)) {
 		ret = PTR_ERR(hsotg->reset);
-		switch (ret) {
-		case -ENOENT:
-		case -ENOTSUPP:
-			hsotg->reset = NULL;
-			break;
-		default:
-			dev_err(hsotg->dev, "error getting reset control %d\n",
-				ret);
-			return ret;
-		}
+		dev_err(hsotg->dev, "error getting reset control %d\n", ret);
+		return ret;
 	}
 
-	if (hsotg->reset)
-		reset_control_deassert(hsotg->reset);
+	reset_control_deassert(hsotg->reset);
 
 	/* Set default UTMI width */
 	hsotg->phyif = GUSBCFG_PHYIF16;
@@ -326,8 +317,7 @@ static int dwc2_driver_remove(struct platform_device *dev)
 	if (hsotg->ll_hw_enabled)
 		dwc2_lowlevel_hw_disable(hsotg);
 
-	if (hsotg->reset)
-		reset_control_assert(hsotg->reset);
+	reset_control_assert(hsotg->reset);
 
 	return 0;
 }