mesa: expose NV_conditional_render on GLES
The extension spec has been updated to include GLES 2 support, so let's enable it there.
v2: fixup ABI-check as well
Signed-off-by: Erik Faye-Lund erik.faye-lund@collabora.com Reviewed-by: Marek Olšák marek.olsak@amd.com