The hardware can only support the PIPE_CAP_PRIMITIVE_RESTART_FIXED_INDEX
subset. This will make it stop advertising the NV_primitive_restart
extension without breaking GLES 3.0 support.

v2: Update features.txt

Reviewed-by: Eric Anholt <eric@anholt.net> (v1)
Reviewed by: Erik Faye-Lund <erik.faye-lund@collabora.com>

Part-of: <!5559>