mesa/main: do not allow depth-texture enums on gles1

mesa/main: do not allow depth-texture enums on gles1

ctx->Extensions.ARB_depth_texture is set regardless of the API that's
used, so checking for those direcly will always allow the enums from
this extensions when they are supported by the driver.

So let's instead check for both ARB_depth_texture and OES_depth_texture,
so we support depth textures on OpenGL and OpenGL ES 2.0+. There's no
extension enabling depth-textures for OpenGL ES 1.x, so we shouldn't
allow those enums there.

This fixes oes_packed_depth_stencil-depth-stencil-texture_gles1 on i965

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>