wdt: nuvoton: Add support for Nuvoton

Add watchdog controller driver for NPCM7xx/npcm8xx

the wdt design of npcm750 and npcm845 is the same.
so the driver can work on npcm750 and npcm845.
about npcm845 wdt dtsi i will followed kernel dts name
to use nuvoton,npcm750-wdt.

Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 5b614cf..03e8e72 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -197,6 +197,14 @@
 	  The watchdog timer is stopped when initialized.
 	  It performs full SoC reset.
 
+config WDT_NPCM
+	bool "Nuvoton watchdog timer support"
+	depends on WDT && ARCH_NPCM
+	help
+	  This enables Nuvoton npcm7xx/npcm8xx watchdog timer driver,
+	  The watchdog timer is stopped when initialized.
+	  It performs full SoC reset.
+
 config WDT_OCTEONTX
 	bool "OcteonTX core watchdog support"
 	depends on WDT && (ARCH_OCTEONTX || ARCH_OCTEONTX2)