watchdog: renesas-wdt: Add support for the R8A77965 WDT

Document support for the Watchdog Timer (WDT) Controller in the Renesas
R-Car M3-N (R8A77965) SoC. No driver update is needed.
Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
[wsa: rebased to v4.17-rc3]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Documentation/devicetree/bindings/watchdog/renesas-wdt.txt

@@ -7,6 +7,7 @@ Required properties:
 	         - "renesas,r7s72100-wdt" (RZ/A1)
 	         - "renesas,r8a7795-wdt" (R-Car H3)
 	         - "renesas,r8a7796-wdt" (R-Car M3-W)
+		 - "renesas,r8a77965-wdt" (R-Car M3-N)
 	         - "renesas,r8a77970-wdt" (R-Car V3M)
 	         - "renesas,r8a77995-wdt" (R-Car D3)