usb: phy: fix return value check of usb_get_phy

usb_get_phy will return -ENODEV if it's not able to find the phy. Hence
fixed all the callers of usb_get_phy to check for this error condition
instead of relying on a non-zero value as success condition.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/am35x.c

@@ -29,6 +29,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/clk.h>
+#include <linux/err.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
@@ -365,7 +366,7 @@ static int am35x_musb_init(struct musb *musb)
 
 	usb_nop_xceiv_register();
 	musb->xceiv = usb_get_phy(USB_PHY_TYPE_USB2);
-	if (!musb->xceiv)
+	if (IS_ERR_OR_NULL(musb->xceiv))
 		return -ENODEV;
 
 	if (is_host_enabled(musb))