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/Makefile b/drivers/watchdog/Makefile
index eef786f..5520d3d 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -44,6 +44,7 @@
 obj-$(CONFIG_WDT_K3_RTI) += rti_wdt.o
 obj-$(CONFIG_WDT_SL28CPLD) += sl28cpld-wdt.o
 obj-$(CONFIG_WDT_SP805) += sp805_wdt.o
+obj-$(CONFIG_WDT_STARFIVE) += starfive_wdt.o
 obj-$(CONFIG_WDT_STM32MP) += stm32mp_wdt.o
 obj-$(CONFIG_WDT_SUNXI) += sunxi_wdt.o
 obj-$(CONFIG_WDT_TANGIER) += tangier_wdt.o