armv7: Add support of ls1021a-iot board

The patch adds support for Freescale ls1021a-iot board.

Signed-off-by: Feng Li <feng.li_2@nxp.com>
[YS: rewrite commit message, fix whitespace in Kconfig]
Reviewed-by: York Sun <york.sun@nxp.com>
16 files changed