A64-OLinuXino board has three variants that have eMMC support. Add support for
eMMC on boards that have it.

This patch has been tested on A64-OLinuXino-1Ge16GW with Linux 5.0 from Debain.
Basic benchmarks using Flexible IO Tester show reasonable performance from the
eMMC.

eMMC - Random Write: 23.1MiB/s
eMMC - Sequential Write: 74.5MiB/s
SD Card - Random Write: 1690KiB/s
SD Card - Sequential Write: 11.0MiB/s

Signed-off-by: Sunil Mohan Adapa <redacted>
Tested-by: Sunil Mohan Adapa <redacted>

From: Martin Ayotte <redacted>
Link: https://github.com/armbian/build/commit/174953de1eb09e6aa1ef7075066b573dba625398
Signed-off-by: Sunil Mohan Adapa <redacted>
---
 .../boot/dts/allwinner/sun50i-a64-olinuxino.dts | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64-olinuxino.dts b/arch/arm64/boot/dts/allwinner/sun50i-a64-olinuxino.dts
index 01a9a52edae4..751273f514fb 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64-olinuxino.dts
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-olinuxino.dts

@@ -81,6 +81,13 @@
                status = "okay";
        };

+       reg_vcc3v3: vcc3v3 {
+               compatible = "regulator-fixed";
+               regulator-name = "vcc3v3";
+               regulator-min-microvolt = <3300000>;
+               regulator-max-microvolt = <3300000>;
+       };
+
        wifi_pwrseq: wifi_pwrseq {
                compatible = "mmc-pwrseq-simple";
                reset-gpios = <&r_pio 0 2 GPIO_ACTIVE_LOW>; /* PL2 */

@@ -155,6 +162,16 @@
        };
 };

+&mmc2 {
+       pinctrl-names = "default";
+       pinctrl-0 = <&mmc2_pins>;
+       vmmc-supply = <&reg_vcc3v3>;