[ARM] mmp: update pxa168_defconfig and include avengers lite support

Signed-off-by: Gavin Gu <gavin.gu@marvell.com>
Signed-off-by: Jing Xiang <jxiang@marvell.com>
Signed-off-by: Jack Ren <jack.ren@marvell.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>