USB: chipidea: add -DDEBUG if debugging is enabled

This patch turns on debugging output if CONFIG_USB_CHIPIDEA_DEBUG is
enabled.

Signed-off-by: Richard Zhao <richard.zhao@freescale.com>
Tested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/chipidea/Makefile b/drivers/usb/chipidea/Makefile
index 57e510f..d92ca32 100644
--- a/drivers/usb/chipidea/Makefile
+++ b/drivers/usb/chipidea/Makefile
@@ -1,3 +1,5 @@
+ccflags-$(CONFIG_USB_CHIPIDEA_DEBUG) := -DDEBUG
+
 obj-$(CONFIG_USB_CHIPIDEA)		+= ci_hdrc.o
 
 ci_hdrc-y				:= core.o