uboot-imx

armv8: ls1012a: Convert CONFIG_LS1012A to Kconfig option ARCH_LS1021A

Move this config to Kconfig option and clean up existing uses.

Signed-off-by: York Sun <york.sun@nxp.com>
CC: Calvin Johnson <calvin.johnson@nxp.com>
CC: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
Reviewed-by: Tom Rini <trini@konsulko.com>