nitrogen6_vm: initial addition, Boundary Devices board

nitrogen6_vm: prefer hannstar7 over lg1280x800
nitrogen6_vm: add IMX_VD38_AUO_B101EW05
nitrogen6_vm: add IMX_VD38_DT070BTFT
nitrogen6_vm.h: CONFIG_IPUV3_CLK 264000000
nitrogen6_vm: setup_dispay is done in fbpanel
nitrogen6_vm: add CONFIG_CMD_GPIO
nitrogen6_vm: explicit fbp_detect_i2c
nitrogen6_vm: use boundary.h
nitrogen6_vm: setup rgb_gpio_pads in board_early_init_f
nitrogen6_vm: change sdcard drive strength
nitrogen6_vm: add CONFIG_SPI_FLASH_SPANSION
nitrogen6_vm: change sdcard drive strength(partial revert)
nitrogen6_vm: add nitrogen6_vm-pt1g_defconfig
nitrogen6_vm: nitrogen6_vm_defconfig add CONFIG_BLOCK_CACHE
nitrogen6_vm: use common code for eth init
nitrogen6_vm: eth.c now in common directory
nitrogen6_vm: move misc_init_r/do_kbd to common
nitrogen6_vm: move mmc_init/ dram_init/ overwrite_console/ common_board_init/ splash_screen_prepare/ board_cfb_skip to common
nitrogen6_vm: add  CONFIG_SPI_FLASH_GIGADEVICE: to defconfigs
nitrogen6_vm: use CONFIG_DEFAULT_HITACHI_HVGA
nitrogen6_vm: use common ddr scripts
nitrogen6_vm: port to v2018.07

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

nitrogen6_vm.h: add basic fastboot support
Only works on eMMC with GPT already present.
nitrogen6_vm: add secure boot option
nitrogen6_vm: update to v2017.01
nitrogen6_vm: update to v2017.03

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>