ARM: shmobile: ape6evm dts: Enable pull-up for GPIO switches

The switches on r8a73a4/ape6evm do not have pull-up registers.  The
schematics say: "Need to use APE6 internal PullUp", hence enable pull-up
using pinctrl.

Without this, the switches don't really work, as the GPIO inputs are
more likely to pick up ghost signals through capacitive coupling than
actual keypresses.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a73a4-ape6evm.dts

@@ -123,6 +123,9 @@ led6 {
 	keyboard {
 		compatible = "gpio-keys";
 
+		pinctrl-names = "default";
+		pinctrl-0 = <&keyboard_pins>;
+
 		zero-key {
 			gpios = <&pfc 324 GPIO_ACTIVE_LOW>;
 			linux,code = <KEY_0>;
@@ -208,6 +211,12 @@ sdhi1_pins: sd1 {
 		renesas,groups = "sdhi1_data4", "sdhi1_ctrl";
 		renesas,function = "sdhi1";
 	};
+
+	keyboard_pins: keyboard {
+		renesas,pins = "PORT324", "PORT325", "PORT326", "PORT327",
+			       "PORT328", "PORT329";
+		bias-pull-up;
+	};
 };
 
 &mmcif0 {