drivers/soc/cmn: Port MC146818 header

BUG=b:305902595
TEST=Verify build and boot on Screebo

Change-Id: Ia0e3453922ded1aca6a9031650ad438b81faa0b8
Signed-off-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/depthcharge/+/5633937
Commit-Queue: Kapil Porwal <kapilporwal@chromium.org>
Tested-by: Kapil Porwal <kapilporwal@chromium.org>
Reviewed-by: Subrata Banik <subratabanik@chromium.org>
2 files changed