arm64: dts: allwinner: h6: add watchdog node

Allwinner H6 has a watchog node which seems broken
on some boards.

Test has been performed on several boards.

Chen-Yu Tsai boards:
Pine H64 - H6448BA 7782 => OK
OrangePi Lite 2 - H8068BA 61C2 => KO

Martin Ayotte boards:
Pine H64 - H8069BA 6892 => OK
OrangePi 3 - HA047BA 69W2 => KO
OrangePi One Plus - H7310BA 6842 => KO
OrangePi Lite2 - H6448BA 6662 => KO

Clément Péron board:
Beelink GS1 - H7309BA 6842 => KO

As it seems not fixable for now, declare the node
but leave it disable with a comment.
Signed-off-by: Clément Péron <peron.clem@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi

@@ -208,6 +208,15 @@ sid: sid@3006000 {
 			reg = <0x03006000 0x400>;
 		};
 
+		watchdog: watchdog@30090a0 {
+			compatible = "allwinner,sun50i-h6-wdt",
+				     "allwinner,sun6i-a31-wdt";
+			reg = <0x030090a0 0x20>;
+			interrupts = <GIC_SPI 50 IRQ_TYPE_LEVEL_HIGH>;
+			/* Broken on some H6 boards */
+			status = "disabled";
+		};
+
 		pio: pinctrl@300b000 {
 			compatible = "allwinner,sun50i-h6-pinctrl";
 			reg = <0x0300b000 0x400>;