mpc85xx/t104x: Enable L2 and CPC cache when resume

When resume from deep sleep, uboot needs to enable L2 and CPC
cache, or they would be keeping unusable in kernel because
kernel didn't enble or initialized them.
This patch didn't change the existing L2 cache enabling code,
just put them in a function.

Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>