usb: common: of_usb_get_maximum_speed to usb_get_maximum_speed

By using the unified device property interface, the function
can be made available for all platforms and not just the
ones using DT.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index 3feebf7..ce71532 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -648,7 +648,7 @@
 			return ret;
 	}
 
-	if (of_usb_get_maximum_speed(dev->of_node) == USB_SPEED_FULL)
+	if (usb_get_maximum_speed(dev) == USB_SPEED_FULL)
 		platdata->flags |= CI_HDRC_FORCE_FULLSPEED;
 
 	platdata->itc_setting = 1;