mediatek: Move watchdog timer code to a common directory

Move watchdog timer (WDT) code which can be reused into a common
directory under soc/mediatek.

BUG=b:80501386
BRANCH=none
TEST=Boots correctly on Elm

Change-Id: Icbeb04f775c3c0fdc18dd198df8591f5c4b6ddce
Signed-off-by: Tristan Shieh <tristan.shieh@mediatek.com>
Reviewed-on: https://review.coreboot.org/27025
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/mediatek/common/include/soc/wdt.h

@@ -1,7 +1,7 @@
 /*
  * This file is part of the coreboot project.
  *
- * Copyright 2015 MediaTek Inc.
+ * Copyright 2018 MediaTek Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by

src/soc/mediatek/common/wdt.c

@@ -1,7 +1,7 @@
 /*
  * This file is part of the coreboot project.
  *
- * Copyright 2015 MediaTek Inc.
+ * Copyright 2018 MediaTek Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by

src/soc/mediatek/mt8173/Makefile.inc

@@ -28,7 +28,7 @@ bootblock-$(CONFIG_DRIVERS_UART) += ../common/uart.c
 endif
 
 bootblock-y += gpio.c gpio_init.c pmic_wrap.c mt6391.c
-bootblock-y += wdt.c
+bootblock-y += ../common/wdt.c
 bootblock-y += mmu_operations.c
 
 ################################################################################
@@ -40,7 +40,7 @@ verstage-$(CONFIG_DRIVERS_UART) += ../common/uart.c
 
 verstage-y += ../common/timer.c
 verstage-y += timer.c
-verstage-y += wdt.c
+verstage-y += ../common/wdt.c
 verstage-$(CONFIG_SPI_FLASH) += flash_controller.c
 verstage-y += gpio.c
 
@@ -74,7 +74,7 @@ ramstage-y += pmic_wrap.c mt6391.c i2c.c
 ramstage-y += mt6311.c
 ramstage-y += da9212.c
 ramstage-y += gpio.c
-ramstage-y += wdt.c
+ramstage-y += ../common/wdt.c
 ramstage-y += pll.c
 ramstage-y += rtc.c