arm64: dts: renesas: r8a77970: Fix PWM3

The pwm3 was incorrectly added with a compatible reference to the
renesas,pwm-r8a7790 (H2) due to a single characther ommision.

Fix the compatible string.

Fixes: de625477 ("arm64: dts: renesas: r8a779{7|8}0: add PWM support")
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Link: https://lore.kernel.org/r/20190912103143.985-1-kieran.bingham+renesas@ideasonboard.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

arch/arm64/boot/dts/renesas/r8a77970.dtsi

@@ -652,7 +652,7 @@ pwm2: pwm@e6e32000 {
 		};
 
 		pwm3: pwm@e6e33000 {
-			compatible = "renesas,pwm-r8a7790", "renesas,pwm-rcar";
+			compatible = "renesas,pwm-r8a77970", "renesas,pwm-rcar";
 			reg = <0 0xe6e33000 0 8>;
 			#pwm-cells = <2>;
 			clocks = <&cpg CPG_MOD 523>;