arm: imx: Add support for Google's Coral Dev Board

Add initial support for Google's Coral Dev Board based on i.MX8MQ.

https://coral.ai/products/dev-board

The Phanbell naming has been used here to match the naming convention
used in Google's U-Boot source tree:

https://coral.googlesource.com/uboot-imx/

Co-developed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Alifer Moraes <alifer.wsdm@gmail.com>
Tested-by: Marco Franchi <marcofrk@gmail.com>

configs/imx8mq_phanbell_defconfig

@@ -0,0 +1,52 @@
+CONFIG_ARM=y
+CONFIG_SPL_SYS_ICACHE_OFF=y
+CONFIG_SPL_SYS_DCACHE_OFF=y
+CONFIG_ARCH_IMX8M=y
+CONFIG_SYS_TEXT_BASE=0x40200000
+CONFIG_ENV_SIZE=0x1000
+CONFIG_ENV_OFFSET=0x400000
+CONFIG_SYS_MALLOC_F_LEN=0x4000
+CONFIG_DM_GPIO=y
+CONFIG_TARGET_IMX8MQ_PHANBELL=y
+CONFIG_SPL_SERIAL_SUPPORT=y
+CONFIG_SPL=y
+CONFIG_CSF_SIZE=0x2000
+CONFIG_SPL_TEXT_BASE=0x7E1000
+CONFIG_FIT=y
+CONFIG_FIT_EXTERNAL_OFFSET=0x3000
+CONFIG_SPL_LOAD_FIT=y
+CONFIG_SPL_FIT_GENERATOR="arch/arm/mach-imx/mkimage_fit_atf.sh"
+CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=arch/arm/mach-imx/imx8m/imximage.cfg"
+CONFIG_SPL_BOARD_INIT=y
+CONFIG_HUSH_PARSER=y
+# CONFIG_BOOTM_NETBSD is not set
+CONFIG_CMD_GPIO=y
+CONFIG_CMD_I2C=y
+CONFIG_CMD_CACHE=y
+CONFIG_CMD_REGULATOR=y
+CONFIG_CMD_EXT2=y
+CONFIG_CMD_EXT4=y
+CONFIG_CMD_EXT4_WRITE=y
+CONFIG_CMD_FAT=y
+CONFIG_OF_CONTROL=y
+CONFIG_DEFAULT_DEVICE_TREE="imx8mq-phanbell"
+CONFIG_ENV_IS_IN_MMC=y
+CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+CONFIG_SAVED_DRAM_TIMING_BASE=0x40000000
+CONFIG_DM_I2C=y
+CONFIG_SYS_I2C_MXC=y
+CONFIG_DM_MMC=y
+CONFIG_SUPPORT_EMMC_BOOT=y
+CONFIG_FSL_USDHC=y
+CONFIG_DM_ETH=y
+CONFIG_PINCTRL=y
+CONFIG_PINCTRL_IMX8M=y
+CONFIG_POWER_DOMAIN=y
+CONFIG_IMX8M_POWER_DOMAIN=y
+CONFIG_DM_REGULATOR=y
+CONFIG_DM_REGULATOR_FIXED=y
+CONFIG_DM_REGULATOR_GPIO=y
+CONFIG_DM_RESET=y
+CONFIG_DM_THERMAL=y
+CONFIG_SD_BOOT=y
+# CONFIG_SPL_DOS_PARTITION is not set