wdt: imx8qxp: add option to control external PMIC wdt via IMX8 SCU

Driver for a PMIC watchdog timer controlled via Siemens SCU firmware
extensions. Only useful on some Siemens i.MX8-based platforms as
special SCFW is needed which provides the needed SCU API.

Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 0e45f0a..b39b254 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -351,6 +351,13 @@
 	   In the single stage mode, when the timeout is reached, your system
 	   will be reset by WS1. The first signal (WS0) is ignored.
 
+config WDT_SIEMENS_PMIC
+	bool "Enable PMIC Watchdog Timer support for Siemens platforms"
+	depends on ARCH_IMX8 && WDT
+	help
+	  Select this to enable the PMIC watchdog driver controlled via
+	  IMX8 SCU API found on Siemens platforms.
+
 config WDT_SL28CPLD
 	bool "sl28cpld watchdog timer support"
 	depends on WDT && SL28CPLD