power_supply: rt9455_charger: Check if CONFIG_USB_PHY is enabled

If CONFIG_USB_PHY is not enabled, struct notifier_block is not defined and
compilation fails. Therefore, the functions that process USB event
notifications are defined only if CONFIG_USB_PHY is enabled.
There is no need to define these functions if CONFIG_USB_PHY is not
enabled, since no USB notifications are received in this case.
Also, since rt9455_set_boost_voltage_before_boost_mode() function is
called only if USB_EVENT_ID notification is received, this function should
also be defined only if CONFIG_USB_PHY is enabled.

Signed-off-by: Anda-Maria Nicolae <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/power/rt9455_charger.c

···
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_USB_PHY)
 /*
  * Before setting the charger into boost mode, boost output voltage is
  * set. This is needed because boost output voltage may differ from battery
···
 
 	return 0;
 }
+#endif
 
 /*
  * Before setting the charger into charge mode, battery regulation voltage is
···
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_USB_PHY)
 static int rt9455_usb_event_none(struct rt9455_info *info,
 				 u8 opa_mode, u8 iaicr)
 {
···
 	}
 	return NOTIFY_DONE;
 }
+#endif
 
 static void rt9455_pwr_rdy_work_callback(struct work_struct *work)
 {