mainboard: Get rid of device_t in ramstage

Use of device_t has been abandoned in ramstage.

Change-Id: I07e00afbbd2c19cf3ea6e08f228eb39e45f1ad0c
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/26983
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/src/mainboard/emulation/qemu-armv7/mainboard.c b/src/mainboard/emulation/qemu-armv7/mainboard.c
index 39c2361..d91d77a 100644
--- a/src/mainboard/emulation/qemu-armv7/mainboard.c
+++ b/src/mainboard/emulation/qemu-armv7/mainboard.c
@@ -50,7 +50,7 @@
 	set_vbe_mode_info_valid(&edid, framebuffer);
 }
 
-static void mainboard_enable(device_t dev)
+static void mainboard_enable(struct device *dev)
 {
 	int discovered;
 	if (!dev) {