drm_hwcomposer: move AddFb/RmFb to reference gem handles

Move drmModeAddFB2 and drmModeRmFB to ensure a reference to the gem
handles are taken while the buffer is in use.

Change-Id: Ib9afdb91144850480ecaac9d73601d887af5fa12
Reviewed-on: https://chrome-internal-review.googlesource.com/200686
Reviewed-by: Stéphane Marchesin <marcheu@google.com>
Commit-Queue: Stéphane Marchesin <marcheu@google.com>
Tested-by: Stéphane Marchesin <marcheu@google.com>
1 file changed