Return the vendor string as hex when it is unknown. ANGLE's vendor strings would include the generic "Unknown" when we did not recognize the driver's vendor ID. Print the vendor ID so that we can future-proof ourselves against new GPU vendors. Bug: chromium:1464799 Change-Id: Idac67b369bc95c3c49eb754e8c681d5930a1f494 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4804365 Reviewed-by: Rafael Cintron <rafael.cintron@microsoft.com> Commit-Queue: Rafael Cintron <rafael.cintron@microsoft.com>