rockchip: Add initial support for the Pinebook Pro laptop from Pine64.

Specification:
- Rockchip RK3399
- 4GB Dual-Channel LPDDR4
- eMMC socket
- mSD card slot
- 128Mbit (16Mb) SPI Flash
- AP6256 for 11AC WiFi + BT5
- 14 inch 1920*1080 eDP MiPi display
- Camera
- USB 3.0, 2.0 ports
- Type-C port with alt-mode display (DP 1.2) and 15W charge
- DC 5V/3A
- optional PCIe slot for NVMe SSD drive

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Tested-by: Vagrant Cascadian <vagrant@debian.org>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/rk3399-pinebook-pro-u-boot.dtsi b/arch/arm/dts/rk3399-pinebook-pro-u-boot.dtsi
new file mode 100644
index 0000000..1a2e24d
--- /dev/null
+++ b/arch/arm/dts/rk3399-pinebook-pro-u-boot.dtsi
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Peter Robinson <pbrobinson at gmail.com>
+ */
+
+#include "rk3399-u-boot.dtsi"
+#include "rk3399-sdram-lpddr4-100.dtsi"
+
+/ {
+	aliases {
+		spi0 = &spi1;
+	};
+
+	chosen {
+		u-boot,spl-boot-order = "same-as-spl", &sdhci, &sdmmc;
+	};
+};
+
+&i2c0 {
+	u-boot,dm-pre-reloc;
+};
+
+&rk808 {
+	u-boot,dm-pre-reloc;
+};
+
+&sdhci {
+	max-frequency = <25000000>;
+	u-boot,dm-pre-reloc;
+};
+
+&sdmmc {
+	max-frequency = <20000000>;
+	u-boot,dm-pre-reloc;
+};
+
+&spiflash {
+	u-boot,dm-pre-reloc;
+};
+
+&vdd_log {
+	regulator-init-microvolt = <950000>;
+};