arm64: dts: rockchip: switch rk3399-gru boards to enable-gpios

The recommended name for enable GPIOs property in regulator-gpio is
enable-gpios.  This is also required by bindings:

  rk3399-gru-bob.dtb: ppvar-sd-card-io: Unevaluated properties are not allowed ('enable-gpio' was unexpected)
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230725142616.157405-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi

@@ -250,7 +250,7 @@ ppvar_sd_card_io: ppvar-sd-card-io {
 		pinctrl-0 = <&sd_io_pwr_en &sd_pwr_1800_sel>;
 
 		enable-active-high;
-		enable-gpio = <&gpio2 2 GPIO_ACTIVE_HIGH>;
+		enable-gpios = <&gpio2 2 GPIO_ACTIVE_HIGH>;
 		gpios = <&gpio2 28 GPIO_ACTIVE_HIGH>;
 		states = <1800000 0x1>,
 			 <3000000 0x0>;