nvc0: disable MS Images for sample_count == 1 on Maxwell

fixes KHR-GL45.multi_bind.dispatch_bind_textures on Maxwell

Suggested-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>

src/gallium/drivers/nouveau/nvc0/nvc0_screen.c

@@ -88,7 +88,7 @@ nvc0_screen_is_format_supported(struct pipe_screen *pscreen,
                  PIPE_BIND_SHARED);
 
    if (bindings & PIPE_BIND_SHADER_IMAGE) {
-      if (sample_count > 1 &&
+      if (sample_count > 0 &&
           nouveau_screen(pscreen)->class_3d >= GM107_3D_CLASS) {
          /* MS images are currently unsupported on Maxwell because they have to
           * be handled explicitly. */