renderer: correct type of vrend_sampler_view::format

Using GLenum here makes it sound like this is used for OpenGL formats,
and not for pipe_format, which it really is. So let's change the type to
reflect what it really is.

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/vrend_renderer.c

@@ -365,7 +365,7 @@ struct vrend_so_target {
 struct vrend_sampler_view {
    struct pipe_reference reference;
    GLuint id;
-   GLuint format;
+   enum pipe_format format;
    GLenum target;
    GLuint val0, val1;
    GLuint gl_swizzle_r;