Fix makefile for x11 dependency flags

BUG=chromium:381565
TEST=build with USE_VAAPI=yes
Change-Id: Ia6fb94593f6adfb35b084311aa9122a9723a9cbc
Reviewed-on: https://chromium-review.googlesource.com/203230
Reviewed-by: Pawel Osciak <posciak@chromium.org>
Tested-by: Kuang-che Wu <kcwu@chromium.org>
Commit-Queue: Kuang-che Wu <kcwu@chromium.org>
1 file changed