Add GGP to Platform Support table Bug: angleproject:4874 Change-Id: I0a497719b00330407b5755d64153315115a95b48 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2318047 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>