ARM: sunxi: Drop mmc0_cd_pin_reference_design pinmux setting

As part of our effort to move pinctrl/GPIO interlocking into the
driver where it belongs, this patch drops the definition and usage
of the mmc0_cd_pin_reference_design pinmux setting for the default
mmc0 card detect GPIO pin.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

arch/arm/boot/dts/sun4i-a10-marsboard.dts

@@ -141,7 +141,7 @@
 
 &mmc0 {
 	pinctrl-names = "default";
-	pinctrl-0 = <&mmc0_pins_a>, <&mmc0_cd_pin_reference_design>;
+	pinctrl-0 = <&mmc0_pins_a>;
 	vmmc-supply = <&reg_vcc3v3>;
 	bus-width = <4>;
 	cd-gpios = <&pio 7 1 GPIO_ACTIVE_HIGH>; /* PH1 */