delay closing of DRM connection as much as possible

ply-image disables all monitors but "main" before it plays boto splash
animation. after it disables the monitors it calls drmClose which causes
kernel to restore previous video mode, re-enabling disabled monitors.
if the monitor syncs before X server starts user can see boot-splash
animation on 2nd monitor. This change moves drmClose to
ply_frame_buffer_close which is never called anyway because we depend
on kernel to teardown everything.

BUG=chrome-os-partner:25917
TEST=boot rambi with HDMI monitor attached. splash screen on 2nd monitor
should be visible for shorter time.

Change-Id: I27cbc046248f9e07227134695db93991032c2f58
Signed-off-by: Dominik Behr <dbehr@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/189124
Reviewed-by: St├ęphane Marchesin <marcheu@chromium.org>
4 files changed