common: add helper function to get plane stride and size in CBM

BUG=b:37615130, b:36769307
TEST=unit tests

Change-Id: I9dfb1a5fd1a36684b89687d0eed9ee6f803b1747
Reviewed-on: https://chromium-review.googlesource.com/487944
Commit-Ready: Ricky Liang <jcliang@chromium.org>
Tested-by: Ricky Liang <jcliang@chromium.org>
Reviewed-by: Heng-ruey Hsu <henryhsu@google.com>
3 files changed