Fixes for: serial: Refactor the FDT, s5p, and ns16550 serial drivers to work together

These changes which implement review feedback were accidentally left out of
a prior change.

BUG=chrome-os-partner:9022
TEST=None

Signed-off-by: Gabe Black <gabeblack@google.com>

Change-Id: Id3881860f8e2b4407a655b510edcd48deadedfa5
Reviewed-on: https://gerrit.chromium.org/gerrit/21858
Commit-Ready: Gabe Black <gabeblack@chromium.org>
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
3 files changed