Add COMPONENT: OS>Kernel>Graphics

See https://tinyurl.com/yxau5sc4 for context.

Bug: 977050
Change-Id: Ib196ebb2f7a29f89106978144f0137c0c917c469
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808457
Auto-Submit: Eric Foo <efoo@chromium.org>
Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Cr-Commit-Position: refs/heads/master@{#698488}

third_party/libdrm/OWNERS

@@ -4,3 +4,5 @@ reveman@chromium.org
 spang@chromium.org
 servolk@chromium.org
 dnicoara@chromium.org
+
+# COMPONENT: OS>Kernel>Graphics