bt2: initial addition, Boundary Devices board

bt2: GPS is thru i2c now
bt2: swap J6/J7
bt2: rename J6/J7 - J5V/J12v
bt2: use nitrogen6x clock.cfg/ddr-setup.cfg
bt2: 1066mhz_4x512mx16.cfg, remove confusing comment
bt2: add/use 1066mhz_4x512mx16-r0.cfg for 4G memory option
bt2: add CONFIG_CMD_GPIO
bt2: explicit fbp_detect_i2c
bt2: add wlmac
bt2: increase refresh rate for 4G-rank0
bt2: setup rgb_gpio_pads in board_early_init_f
bt2: add CONFIG_SPI_FLASH_SPANSION
bt2: bt2_2g_defconfig add CONFIG_BLOCK_CACHE
bt2_4g: bt2_4g_defconfig add CONFIG_BLOCK_CACHE
bt2: use common code for eth init
bt2: eth.c now in common directory
bt2: move mmc_init/ dram_init/ overwrite_console/ common_board_init/ splash_screen_prepare/ board_cfb_skip to common
bt2: use common 1066mhz_4x256mx16.cfg
bt2: add  CONFIG_SPI_FLASH_GIGADEVICE: to defconfigs
bt2: use common ddr scripts
bt2: port to v2018.07

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

bt2: update to v2017.01
bt2: update to v2017.03
bt2: move misc_init_r/do_kbd to common

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