watchdog: Add StarFive Watchdog driver

Add to support StarFive watchdog driver. The driver is imported from
linux kernel's drivers/watchdog/starfive-wdt.c without jh7100 support
because there is no support of jh7100 SoC in u-boot yet.
Howver, this patch has been kept the variant coding style because JH7100
can be added later and have a consistency with the linux driver.

Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 07fc494..5697261 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -344,6 +344,13 @@
 	  Enable the STM32 watchdog (IWDG) driver. Enable support to
 	  configure STM32's on-SoC watchdog.
 
+config WDT_STARFIVE
+	bool "StarFive watchdog timer support"
+	depends on WDT
+	imply WATCHDOG
+	help
+	  Enable support for the watchdog timer of StarFive JH7110 SoC.
+
 config WDT_SUNXI
 	bool "Allwinner sunxi watchdog timer support"
 	depends on WDT && ARCH_SUNXI