serrano: Dexopt system to cache

Change-Id: I5141f38913b9bb51b70d12692d4c5f0887b7840d
serrano: Fix user build issues

Change-Id: If77a173ef4cba92cd0b04ca5a6964310126d38f9
Signed-off-by: Willi Ye <williye97@gmail.com>

Conflicts:
	BoardConfigCommon.mk