dts: sun8i-h3: correct UART3 pin definitions

In a previous commit, I made a copy/paste error in the pinmux
definitions of UART3: PG{13,14} instead of PA{13,14}. This commit takes
care of that. I have tested this commit on Orange Pi PC and Orange Pi
Plus, and it works for these boards.

Fixes: e3d11d3c ("dts: sun8i-h3: add pinmux definitions for
UART2-3")
Signed-off-by: Jorik Jonker <jorik@kippendief.biz>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/boot/dts/sun8i-h3.dtsi

@@ -410,7 +410,7 @@ uart2_pins: uart2 {
 			};
 
 			uart3_pins: uart3 {
-				allwinner,pins = "PG13", "PG14";
+				allwinner,pins = "PA13", "PA14";
 				allwinner,function = "uart3";
 				allwinner,drive = <SUN4I_PINCTRL_10_MA>;
 				allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;