drivers: watchdog: litex: add litex watchdog

this adds a driver for the litex watchdog.

Signed-off-by: Fin Maaß <f.maass@vogl-electronic.com>

boards/enjoydigital/litex_vexriscv/litex_vexriscv.dts

@@ -17,6 +17,10 @@
 		zephyr,sram = &ram0;
 	};
 
+	aliases {
+		watchdog0 = &wdt0;
+	};
+
 	ram0: memory@40000000 {
 		device_type = "memory";
 		reg = <0x40000000 0x10000000>;
@@ -36,6 +40,10 @@
 	status = "okay";
 };
 
+&wdt0 {
+	status = "okay";
+};
+
 &mdio0 {
 	status = "okay";
 };

boards/enjoydigital/litex_vexriscv/litex_vexriscv.yaml

@@ -12,8 +12,12 @@ toolchain:
   - zephyr
 ram: 262144
 supported:
+  - gpio
+  - uart
   - spi
   - i2s
+  - i2c
+  - watchdog
 testing:
   ignore_tags:
     - bluetooth