* LUMA formats don't have sized versions without specific extensions.
 * This allows a more direct translation, the driver should do the right
   thing.

BUG=angleproject:884
BUG=angleproject:1145

Change-Id: I2ad13db7216eb7c715621a237b13ae9e3035310a
Reviewed-on: https://chromium-review.googlesource.com/322694Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>