cnt: initial addition, Boundary Devices board

cnt: add defconfig for 1GB of RAM version
cnt: fix boot devs configuration
cnt: update to v2017.01
cnt: update to v2017.03
cnt.h: add custom BOOT_TARGET_DEVICES priority

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

cnt: print ethernet phy name (AR8035)
cnt.h: CONFIG_IPUV3_CLK 264000000
cnt: use nitrogen6x clock.cfg/ddr-setup.cfg
cnt: add CONFIG_CMD_GPIO
cnt: explicit fbp_detect_i2c
cnt: verify port in board_ehci_hcd_init
cnt: preboot_keys is not defined, remove call
cnt: use boundary.h
cnt: add CONFIG_SPI_FLASH_SPANSION
cnt: 1066mhz_4x256mx16.cfg: update calibration for new spin of board
cnt: cnt1g_defconfig add CONFIG_BLOCK_CACHE
cnt2g: cnt2g_defconfig add CONFIG_BLOCK_CACHE
cnt: 1066mhz_4x256mx16.cfg: increase cycles for tFAW/tRRD
cnt2g: change ddr to 500.21 MHz
cnt: use common code for eth init
cnt: eth.c now in common directory
cnt: move misc_init_r/do_kbd to common
cnt: move mmc_init/ dram_init/ overwrite_console/ common_board_init/ splash_screen_prepare/ board_cfb_skip to common
cnt: use common 1066mhz_4x256mx16.cfg
cnt: use common 1066mhz_4x128mx16.cfg
cnt: add  CONFIG_SPI_FLASH_GIGADEVICE: to defconfigs
cnt: use common ddr scripts
cnt: port to v2018.07

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