usb: chipidea: udc: add maximum-speed = full-speed option

This patch makes it possible to set the chipidea udc into full-speed only mode.
It is set by the oftree property "maximum-speed = full-speed".

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/usb/chipidea.h b/include/linux/usb/chipidea.h
index 708bd11..bbe779f 100644
--- a/include/linux/usb/chipidea.h
+++ b/include/linux/usb/chipidea.h
@@ -25,6 +25,7 @@
 	 */
 #define CI_HDRC_DUAL_ROLE_NOT_OTG	BIT(4)
 #define CI_HDRC_IMX28_WRITE_FIX		BIT(5)
+#define CI_HDRC_FORCE_FULLSPEED		BIT(6)
 	enum usb_dr_mode	dr_mode;
 #define CI_HDRC_CONTROLLER_RESET_EVENT		0
 #define CI_HDRC_CONTROLLER_STOPPED_EVENT	1