dt-bindings: watchdog: Add support for TI K3 RTI watchdog

TI K3 SoCs contain an RTI (Real Time Interrupt) module which can be
used to implement a windowed watchdog functionality.

Signed-off-by: Tero Kristo <t-kristo@ti.com>

Documentation/devicetree/bindings/watchdog/ti,rti-wdt.txt

@@ -0,0 +1,18 @@
+Texas Instruments RTI (Real Time Interrupt) module. RTI is used for
+implementing a watchdog on TI SoCs.
+
+Required properties:
+	compatible	= "ti,rti-wdt";
+	reg		= Physical IO space for RTI
+	clocks		= Functional clock for the RTI
+
+Example:
+
+main_rti0: rti@2200000 {
+	compatible = "ti,rti-wdt";
+	reg = <0x0 0x2200000 0x0 0x100>;
+	clocks = <&k3_clks 252 1>;
+	power-domains = <&k3_pds 252 TI_SCI_PD_EXCLUSIVE>;
+	assigned-clocks = <&k3_clks 252 1>;
+	assigned-clock-parents = <&k3_clks 252 5>;
+};