MIPS: ath79: add common watchdog device

All supported SoCs have a built-in hardware watchdog driver. This patch
registers a platform_device for that to make it usable.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1955/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/ath79/dev-common.h b/arch/mips/ath79/dev-common.h
index 248622c..0f514e1 100644
--- a/arch/mips/ath79/dev-common.h
+++ b/arch/mips/ath79/dev-common.h
@@ -13,5 +13,6 @@
 #define _ATH79_DEV_COMMON_H
 
 void ath79_register_uart(void);
+void ath79_register_wdt(void);
 
 #endif /* _ATH79_DEV_COMMON_H */