usb: phy: generic: allow multiples calls to usb_phy_generic_register()

it's now very easy to return a platform_device pointer
and have the caller pass it as argument when calling
usb_phy_generic_unregister().

Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/musb/am35x.c b/drivers/usb/musb/am35x.c
index 05459b5..0a34dd8 100644
--- a/drivers/usb/musb/am35x.c
+++ b/drivers/usb/musb/am35x.c
@@ -85,6 +85,7 @@
 struct am35x_glue {
 	struct device		*dev;
 	struct platform_device	*musb;
+	struct platform_device	*phy;
 	struct clk		*phy_clk;
 	struct clk		*clk;
 };
@@ -503,7 +504,9 @@
 
 	pdata->platform_ops		= &am35x_ops;
 
-	usb_phy_generic_register();
+	glue->phy = usb_phy_generic_register();
+	if (IS_ERR(glue->phy))
+		goto err7;
 	platform_set_drvdata(pdev, glue);
 
 	pinfo = am35x_dev_info;
@@ -517,11 +520,14 @@
 	if (IS_ERR(musb)) {
 		ret = PTR_ERR(musb);
 		dev_err(&pdev->dev, "failed to register musb device: %d\n", ret);
-		goto err7;
+		goto err8;
 	}
 
 	return 0;
 
+err8:
+	usb_phy_generic_unregister(glue->phy);
+
 err7:
 	clk_disable(clk);
 
@@ -546,7 +552,7 @@
 	struct am35x_glue	*glue = platform_get_drvdata(pdev);
 
 	platform_device_unregister(glue->musb);
-	usb_phy_generic_unregister();
+	usb_phy_generic_unregister(glue->phy);
 	clk_disable(glue->clk);
 	clk_disable(glue->phy_clk);
 	clk_put(glue->clk);