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>

include/configs/pinebook-pro-rk3399.h

@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2016 Rockchip Electronics Co., Ltd
+ * Copyright (C) 2020 Peter Robinson <pbrobinson at gmail.com>
+ */
+
+#ifndef __PINEBOOK_PRO_RK3399_H
+#define __PINEBOOK_PRO_RK3399_H
+
+#define ROCKCHIP_DEVICE_SETTINGS \
+		"stdin=serial,usbkbd\0" \
+		"stdout=serial,vidconsole\0" \
+		"stderr=serial,vidconsole\0"
+
+#include <configs/rk3399_common.h>
+
+#if defined(CONFIG_ENV_IS_IN_MMC)
+#define CONFIG_SYS_MMC_ENV_DEV 0
+#elif defined(CONFIG_ENV_IS_IN_SPI_FLASH)
+#define CONFIG_ENV_SECT_SIZE		(8 * 1024)
+#endif
+
+#undef CONFIG_SYS_SPI_U_BOOT_OFFS
+#define CONFIG_SYS_SPI_U_BOOT_OFFS	1024 * 512
+
+#define SDRAM_BANK_SIZE			(2UL << 30)
+
+#endif