rockchip: add support for rk3288 PopMetal board

PopMetal is a rockchip rk3288 based board made by ChipSpark, which has
many interface such as HDMI, VGA, USB, micro-SD card, WiFi, Audio and
Gigabit Ethernet.

Signed-off-by: Ziyuan Xu <xzy.xu@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>

configs/popmetal-rk3288_defconfig

@@ -0,0 +1,65 @@
+CONFIG_ARM=y
+CONFIG_ARCH_ROCKCHIP=y
+CONFIG_SYS_MALLOC_F_LEN=0x2000
+CONFIG_ROCKCHIP_RK3288=y
+CONFIG_TARGET_POPMETAL_RK3288=y
+CONFIG_SPL_STACK_R_ADDR=0x80000
+CONFIG_DEFAULT_DEVICE_TREE="rk3288-popmetal"
+CONFIG_SPL_STACK_R=y
+CONFIG_SPL_STACK_R_MALLOC_SIMPLE_LEN=0x2000
+CONFIG_HUSH_PARSER=y
+CONFIG_CMD_BOOTZ=y
+# CONFIG_CMD_IMLS is not set
+CONFIG_CMD_MMC=y
+CONFIG_CMD_SF=y
+CONFIG_CMD_SPI=y
+CONFIG_CMD_I2C=y
+CONFIG_CMD_GPIO=y
+# CONFIG_CMD_SETEXPR is not set
+CONFIG_CMD_DHCP=y
+CONFIG_CMD_MII=y
+CONFIG_CMD_PING=y
+CONFIG_CMD_CACHE=y
+CONFIG_CMD_TIME=y
+CONFIG_CMD_PMIC=y
+CONFIG_CMD_REGULATOR=y
+CONFIG_CMD_EXT2=y
+CONFIG_CMD_EXT4=y
+CONFIG_CMD_FAT=y
+CONFIG_CMD_FS_GENERIC=y
+CONFIG_SPL_OF_CONTROL=y
+CONFIG_OF_SPL_REMOVE_PROPS="pinctrl-0 pinctrl-names clock-names interrupt-parent assigned-clocks assigned-clock-rates assigned-clock-parents"
+CONFIG_REGMAP=y
+CONFIG_SPL_REGMAP=y
+CONFIG_SYSCON=y
+CONFIG_SPL_SYSCON=y
+# CONFIG_SPL_SIMPLE_BUS is not set
+CONFIG_CLK=y
+CONFIG_SPL_CLK=y
+CONFIG_ROCKCHIP_GPIO=y
+CONFIG_SYS_I2C_ROCKCHIP=y
+CONFIG_SYSRESET=y
+CONFIG_DM_MMC=y
+CONFIG_ROCKCHIP_DWMMC=y
+CONFIG_PINCTRL=y
+CONFIG_SPL_PINCTRL=y
+# CONFIG_SPL_PINCTRL_FULL is not set
+CONFIG_ROCKCHIP_RK3288_PINCTRL=y
+CONFIG_DM_PMIC=y
+CONFIG_PMIC_RK808=y
+CONFIG_DM_REGULATOR=y
+CONFIG_REGULATOR_RK808=y
+CONFIG_DM_REGULATOR_FIXED=y
+CONFIG_DM_PWM=y
+CONFIG_PWM_ROCKCHIP=y
+CONFIG_RAM=y
+CONFIG_SPL_RAM=y
+CONFIG_DEBUG_UART=y
+CONFIG_DEBUG_UART_BASE=0xff690000
+CONFIG_DEBUG_UART_CLOCK=24000000
+CONFIG_DEBUG_UART_SHIFT=2
+CONFIG_SYS_NS16550=y
+CONFIG_USE_PRIVATE_LIBGCC=y
+CONFIG_USE_TINY_PRINTF=y
+CONFIG_CMD_DHRYSTONE=y
+CONFIG_ERRNO_STR=y