mips: bmips: bcm63268: add TWD block binding

TWD is an MFD block that contains timers, watchdog & some clocks / reset
controller.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/boot/dts/brcm/bcm63268.dtsi

@@ -105,15 +105,21 @@ periph_intc: interrupt-controller@10000020 {
 			interrupts = <2>, <3>;
 		};
 
-		wdt: watchdog@1000009c {
+		timer-mfd@10000080 {
+			compatible = "brcm,bcm7038-twd", "simple-mfd", "syscon";
+			reg = <0x10000080 0x30>;
+			ranges = <0x0 0x10000080 0x30>;
+
+			wdt: watchdog@1c {
 				compatible = "brcm,bcm7038-wdt";
-			reg = <0x1000009c 0xc>;
+				reg = <0x1c 0xc>;
 
 				clocks = <&periph_osc>;
 				clock-names = "refclk";
 
 				timeout-sec = <30>;
 			};
+		};
 
 		uart0: serial@10000180 {
 			compatible = "brcm,bcm6345-uart";