shader: on GLES most image formats always require the specification of ro/wo

Closes: #16

Fixes:
  dEQP-GLES31.functional.image_load_store.*.format_reinterpret.*
  dEQP-GLES31.functional.image_load_store.*.image_size.writeonly_*
  dEQP-GLES31.functional.image_load_store.*.load_store.*
  dEQP-GLES31.functional.image_load_store.*.qualifiers.restrict
  dEQP-GLES31.functional.image_load_store.*.store.*

v2: remove superfluous check (Erik)

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/vrend_shader.c

@@ -4304,7 +4304,9 @@ static void *emit_image_decl(const struct dump_ctx *ctx, char *glsl_hdr,
 
    if (!image->decl.Writable)
       access = "readonly ";
-   else if (!image->decl.Format)
+   else if ((image->decl.Format != PIPE_FORMAT_R32_FLOAT) &&
+            (image->decl.Format != PIPE_FORMAT_R32_SINT) &&
+            (image->decl.Format != PIPE_FORMAT_R32_UINT))
       access = "writeonly ";
 
    if (ctx->cfg->use_gles) { /* TODO: enable on OpenGL 4.2 and up also */