Support optional board specific default RPi firmware configuration file (config.txt). Also rename from boot-env.txt to config.txt since this file is not read by the U-Boot boot loader but the Raspberry Pi specific boot firmware.
Support optional board specific default RPi firmware configuration file (config.txt). Also rename from boot-env.txt to config.txt since this file is not read by the U-Boot boot loader but the Raspberry Pi specific boot firmware.