No iMX platforms have supported ATAG-based booting. They have however
re-used the CONFIG_SERIAL_TAG option as a way to enable support of
reading the OTP fuses and setting the serial# environment variable in
some cases. Change the warp7 support to use this symbol, use this for
updating the rest of the imx7 code, and update the imx8 conditionals.
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP i.MX U-Boot Team <uboot-imx@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
b9d66a061b