mb/google/rauru: Setup USB host in ramstage

Add usb host function support.

TEST=read usb data successfully.
BUG=b:317009620

Signed-off-by: Mingjin Ge <mingjin.ge@mediatek.corp-partner.google.com>
Change-Id: I5d081ff3e7367b87fab5ebdcb148c9005ab583f5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84022
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>

src/mainboard/google/rauru/mainboard.c

@@ -1,10 +1,11 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <device/device.h>
+#include <soc/usb.h>
 
 static void mainboard_init(struct device *dev)
 {
-	/* TODO: add mainboard init */
+	setup_usb_host();
 }
 
 static void mainboard_enable(struct device *dev)