mediatek: Refactor to sharing code among similar SOCs

This patch refactor cbmem and timer code which will be reused among
similar SOCs.

BUG=b:80501386
BRANCH=none
TEST=the refactored code works fine on the new platform (with the rest
     of the patches applied) and Elm platform

Change-Id: I397ebdc0c97c7616bd547022d2ce2a8f08f3c232
Signed-off-by: Tristan Shieh <tristan.shieh@mediatek.com>
Reviewed-on: https://review.coreboot.org/26881
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
5 files changed