rockchip: rk3399: Add Nanopi NEO4 board support

Add initial support for Nanopi NEO4 board.

Specification
- Rockchip RK3399
- 1GB DDR3-1866
- SD card slot
- eMMC Socket
- RTL8211E 1Gbps
- AP6212 WiFI/BT
- HDMI In/Out, DP, MIPI CSI
- USB 3.0, 2.0
- USB Type C power and data
- GPIO expansion ports
- DC 5V/3A

Commit details of rk3399-nanopi-neo4.dts sync from Linux:
"arm64: dts: rockchip: Add Nanopi NEO4 initial support"
(sha1: 092470b537f19788d957aed12d835a179b606014)

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/nanopi-neo4-rk3399_defconfig b/configs/nanopi-neo4-rk3399_defconfig
new file mode 100644
index 0000000..97a94cb
--- /dev/null
+++ b/configs/nanopi-neo4-rk3399_defconfig
@@ -0,0 +1,60 @@
+CONFIG_ARM=y
+CONFIG_ARCH_ROCKCHIP=y
+CONFIG_SYS_TEXT_BASE=0x00200000
+CONFIG_SPL_LIBCOMMON_SUPPORT=y
+CONFIG_SPL_LIBGENERIC_SUPPORT=y
+CONFIG_SYS_MALLOC_F_LEN=0x4000
+CONFIG_ROCKCHIP_RK3399=y
+CONFIG_ROCKCHIP_SPL_RESERVE_IRAM=0x50000
+CONFIG_DEBUG_UART_BASE=0xFF1A0000
+CONFIG_DEBUG_UART_CLOCK=24000000
+CONFIG_SPL_STACK_R_ADDR=0x80000
+CONFIG_DEBUG_UART=y
+CONFIG_NR_DRAM_BANKS=1
+CONFIG_DEFAULT_FDT_FILE="rockchip/rk3399-nanopi-neo4.dtb"
+# CONFIG_DISPLAY_CPUINFO is not set
+CONFIG_DISPLAY_BOARDINFO_LATE=y
+CONFIG_SPL_STACK_R=y
+CONFIG_SPL_STACK_R_MALLOC_SIMPLE_LEN=0x10000
+CONFIG_CMD_BOOTZ=y
+CONFIG_CMD_GPT=y
+CONFIG_CMD_MMC=y
+CONFIG_CMD_SF=y
+CONFIG_CMD_USB=y
+# CONFIG_CMD_SETEXPR is not set
+CONFIG_CMD_TIME=y
+CONFIG_SPL_OF_CONTROL=y
+CONFIG_DEFAULT_DEVICE_TREE="rk3399-nanopi-neo4"
+CONFIG_OF_SPL_REMOVE_PROPS="pinctrl-0 pinctrl-names clock-names interrupt-parent assigned-clocks assigned-clock-rates assigned-clock-parents"
+CONFIG_TPL=y
+CONFIG_ENV_IS_IN_MMC=y
+CONFIG_ROCKCHIP_GPIO=y
+CONFIG_SYS_I2C_ROCKCHIP=y
+CONFIG_MMC_DW=y
+CONFIG_MMC_DW_ROCKCHIP=y
+CONFIG_MMC_SDHCI=y
+CONFIG_MMC_SDHCI_ROCKCHIP=y
+CONFIG_DM_ETH=y
+CONFIG_ETH_DESIGNWARE=y
+CONFIG_GMAC_ROCKCHIP=y
+CONFIG_PMIC_RK8XX=y
+CONFIG_REGULATOR_PWM=y
+CONFIG_REGULATOR_RK8XX=y
+CONFIG_PWM_ROCKCHIP=y
+CONFIG_BAUDRATE=1500000
+CONFIG_DEBUG_UART_SHIFT=2
+CONFIG_SYSRESET=y
+CONFIG_USB=y
+CONFIG_USB_XHCI_HCD=y
+CONFIG_USB_XHCI_DWC3=y
+CONFIG_USB_EHCI_HCD=y
+CONFIG_USB_EHCI_GENERIC=y
+CONFIG_USB_HOST_ETHER=y
+CONFIG_USB_ETHER_ASIX=y
+CONFIG_USB_ETHER_ASIX88179=y
+CONFIG_USB_ETHER_MCS7830=y
+CONFIG_USB_ETHER_RTL8152=y
+CONFIG_USB_ETHER_SMSC95XX=y
+CONFIG_USE_TINY_PRINTF=y
+CONFIG_SPL_TINY_MEMSET=y
+CONFIG_ERRNO_STR=y