glsl: add missing types for buffer images

Type of GLSL_SAMPLER_DIM_BUF can be sampler or image.

Spotted while trying to run dEQP tests related to
ARB_shader_image_load_store.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Tested-by: Ilia Mirkin <imirkin@alum.mit.edu>
1 file changed