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/include/linux/usb/usb_phy_generic.h b/include/linux/usb/usb_phy_generic.h
index c00176d..8346bcc 100644
--- a/include/linux/usb/usb_phy_generic.h
+++ b/include/linux/usb/usb_phy_generic.h
@@ -15,14 +15,15 @@
 
 #if defined(CONFIG_NOP_USB_XCEIV) || (defined(CONFIG_NOP_USB_XCEIV_MODULE) && defined(MODULE))
 /* sometimes transceivers are accessed only through e.g. ULPI */
-extern void usb_phy_generic_register(void);
-extern void usb_phy_generic_unregister(void);
+extern struct platform_device *usb_phy_generic_register(void);
+extern void usb_phy_generic_unregister(struct platform_device *);
 #else
-static inline void usb_phy_generic_register(void)
+static inline struct platform_device *usb_phy_generic_register(void)
 {
+	return NULL;
 }
 
-static inline void usb_phy_generic_unregister(void)
+static inline void usb_phy_generic_unregister(struct platform_device *pdev)
 {
 }
 #endif