watchdog: ftwdt010: return a previously deleted driver now ported to DM

The ftwdt010 watchdog driver was deleted by
commit 11232139e399 ("nds32: Remove the architecture")

Return it to the codebase in a DM compatible form. Enable it in
sandbox_defconfig to test compilability.
Another platform using ftwdt010 will be submitted later.

Signed-off-by: Sergei Antonov <saproj@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 35c42dd..668942e 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -368,4 +368,11 @@
 	  Enable driver model for watchdog timer in SPL.
 	  This is similar to CONFIG_WDT in U-Boot.
 
+config WDT_FTWDT010
+	bool "Faraday Technology ftwdt010 watchdog timer support"
+	depends on WDT
+	imply WATCHDOG
+	help
+	  Faraday Technology ftwdt010 watchdog is an architecture independent
+	  watchdog. It is usually used in SoC chip design.
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