CHROMIUM: drm/exynos: Remove panel_ops->commit

CHROMIUM: drm/exynos: Remove panel_ops->commit

The explicit panel_ops->commit() functions are really just doing what
DPMS(On) should be doing.  In fact, hdmi_commit literally gets called
twice in the mode_set path: once in DPMS(On) and again in the explicitly
by exynos_drm_encoder_commit().

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
BUG=chromium:189108
TEST=Sanity check LCD display
TEST=Sanity check HDMI attached monitor at Boot
TEST=Sanity check HDMI attached monitor hotplug 2 times
TEST=run_remote_tests.sh --board=daisy --remote=${IP} power_Resume/control$

Change-Id: I07ce63255d5d209b127babd24213f70e42131185
Reviewed-on: https://gerrit.chromium.org/gerrit/47755
Commit-Queue: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Tested-by: Daniel Kurtz <djkurtz@chromium.org>