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>
diff --git a/drivers/usb/musb/davinci.c b/drivers/usb/musb/davinci.c
index 582268d..f649204 100644
--- a/drivers/usb/musb/davinci.c
+++ b/drivers/usb/musb/davinci.c
@@ -28,6 +28,7 @@
 #include <linux/list.h>
 #include <linux/delay.h>
 #include <linux/clk.h>
+#include <linux/err.h>
 #include <linux/io.h>
 #include <linux/gpio.h>
 #include <linux/platform_device.h>
@@ -385,7 +386,7 @@
 
 	usb_nop_xceiv_register();
 	musb->xceiv = usb_get_phy(USB_PHY_TYPE_USB2);
-	if (!musb->xceiv)
+	if (IS_ERR_OR_NULL(musb->xceiv))
 		goto unregister;
 
 	musb->mregs += DAVINCI_BASE_OFFSET;