graphics_SanAngeles: support null platform

Freon boards now support only EGL_PLATFORM_NULL and minigbm so use
WAFFLE_PLATFORM_NULL.

Platform arg parsing is moved to the SanAngeles executable, since that
is where we ultimately want it, and the attempt to factor it out to
graphics_utils.py was cumbersome and not used by anything else.

The waffle_window_show() call was moved because in WAFFLE_PLATFORM_NULL
it must happen before waffle_make_current().

Restored the depth buffer configuration that was accidentally removed
during porting to waffle.

On freon, stop ui in order to mode set.

BUG=chromium:468328
TEST=test_that -b samus -i trybot-samus-paladin/... :lab: graphics_SanAngeles
TEST=test_that -b lumpy -i trybot-lumpy-paladin/... :lab: graphics_SanAngeles
TEST=test_that -b daisy -i trybot-daisy-paladin/... :lab: graphics_SanAngeles
CQ-DEPEND=CL:260993

Change-Id: Idb3aa5a8024f920beec2364a9701bc5455acb602
Reviewed-on: https://chromium-review.googlesource.com/260995
Reviewed-by: Ilja Friedel <ihf@chromium.org>
Commit-Queue: Frank Henigman <fjhenigman@chromium.org>
Tested-by: Frank Henigman <fjhenigman@chromium.org>
3 files changed