fievel: Initialize the buzzer gpio

Initialize the gpio for buzzer which would be used in depthcharge.

BUG=chrome-os-partner:59202
BRANCH=veyron
TEST=tested with CL:406773

Change-Id: Ie17fb5959d572b4ba284ff86c3a1fa5527d4526e
Signed-off-by: ZhengShunQian <zhengsq@rock-chips.com>
Reviewed-on: https://chromium-review.googlesource.com/407127
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/mainboard/google/veyron_fievel/mainboard.c

@@ -110,6 +110,7 @@ static void configure_hdmi(void)
 static void mainboard_init(device_t dev)
 {
 	gpio_output(GPIO_RESET, 0);
+	gpio_output(GPIO(7, A, 5), 0); /* Init buzzer gpio for depthcharge */
 
 	enable_5v_drv();
 	configure_usb();