google/oak: Configurate SD card detection pin

BRANCH=none
BUG=chrome-os-partner:47609
TEST=remove servo board connection and insert/remove an empty SD card
     in recovery mode.

Change-Id: I89a1cb6914d634f07ff71b9793eb29b711381524
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: d21bf091a576574cb9e976447ee2b9a69748d2b6
Original-Change-Id: I2083605c9ad88841885dfaad48dcd27e6fb5161d
Original-Signed-off-by: Yidi Lin <yidi.lin@mediatek.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/313073
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/13099
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/mainboard/google/oak/mainboard.c

@@ -110,6 +110,9 @@ static void mainboard_init(device_t dev)
 	 */
 	mt6391_gpio_output(MT6391_KP_ROW2, 1);
 
+	/* Config SD card detection pin */
+	gpio_input(PAD_EINT1); /* SD_DET */
+
 	configure_audio();
 	configure_backlight();
 	configure_usb();