powerpc/t2080rdb: update ddr to support 1866MT/s

Support SODIMM D3XP12081XL10AA 1866MT/s on T2080RDB.
Enable CONFIG_CMD_MEMTEST as well.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
2 files changed