vrend: assume gl_colorspace also when no context type is set

when virgl_renderer_init is called from qemu for initializing D-GL
no context type flags are set and the context remains at NONE.
Assume in this case that gl_colorspace is true, otherwise the
feat_srgb_write_control flag will be cleared and the guest only
gets OpenGL 2.1 compatibility.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Elie Tournier <elie.tournier@collabora.com>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/virglrenderer.c

@@ -208,7 +208,8 @@ int virgl_has_gl_colorspace(void)
    if (egl_info)
       egl_colorspace = virgl_has_egl_khr_gl_colorspace(egl_info);
 #endif
-   return use_context == CONTEXT_GLX ||
+   return use_context == CONTEXT_NONE ||
+         use_context == CONTEXT_GLX ||
          (use_context == CONTEXT_EGL && egl_colorspace);
 }