glsl: add missing check for samplers in set_opaque_binding()

Like images, this prevents out-of-bound access when the explicit
binding layout qualifier is used with an array which contains
too much samplers.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>

src/compiler/glsl/link_uniform_initializers.cpp

@@ -135,6 +135,8 @@ set_opaque_binding(void *mem_ctx, gl_shader_program *prog,
             if (storage->type->is_sampler() && storage->opaque[sh].active) {
                for (unsigned i = 0; i < elements; i++) {
                   const unsigned index = storage->opaque[sh].index + i;
+                  if (index >= ARRAY_SIZE(shader->Program->SamplerUnits))
+                     break;
                   shader->Program->SamplerUnits[index] =
                      storage->storage[i].i;
                }