sp: initial addition, Boundary Devices board

sp.h: CONFIG_IPUV3_CLK 264000000
sp: setup_dispay is done in fbpanel
sp: add CONFIG_CMD_GPIO
sp: explicit fbp_detect_i2c
sp: verify port in board_ehci_hcd_init
sp: use boundary.h
sp: add CONFIG_SPI_FLASH_SPANSION
sp: sp_defconfig add CONFIG_BLOCK_CACHE
sp: use common code for eth init
sp: eth.c now in common directory
sp: move misc_init_r/do_kbd to common
sp: move mmc_init/ dram_init/ overwrite_console/ common_board_init/ splash_screen_prepare/ board_cfb_skip to common
sp: add  CONFIG_SPI_FLASH_GIGADEVICE: to defconfigs
sp: add sp_s512m.cfg
sp: port to v2018.07

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

sp: update to v2017.01
sp: update to v2017.03
sp.h: add custom BOOT_TARGET_DEVICES priority

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