ARM: dts: rockchip: rk3128: redefine sdmmc_pwren as GPIO function

For rk3128 reference design, sdmmc_pwren is used as a GPIO.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Change-Id: If954337fe87da85eb7a088714ac6b0a5777c3cb7

arch/arm/boot/dts/rk3128.dtsi

@@ -169,6 +169,10 @@
 		 <&qos_vip0>;
 };
 
+&sdmmc_pwren {
+	rockchip,pins = <1 RK_PB6 RK_FUNC_GPIO &pcfg_pull_default>;
+};
+
 &video_phy {
 	status = "okay";
 };