Chameleon: check TV level from projected calibration image

instead of looking at DUT platform.

It's observed that peach_pi may output video signal at either TV or
PC level. This patch fixes it by checking the extrema of the projected
calibration image on demand and unlevels the image back to PC level if
it's at TV level.

BUG=chromium:429573
TEST=run display_ResolutionList.extended on peach_pi and see it passed.

Change-Id: Ic771cf3d0a954bc2026cd55e7fe084255fb746ce
Reviewed-on: https://chromium-review.googlesource.com/227112
Tested-by: Hung-ying Tyan <tyanh@chromium.org>
Reviewed-by: Wai-Hong Tam <waihong@chromium.org>
Commit-Queue: Hung-ying Tyan <tyanh@chromium.org>
2 files changed