svga: implement sRGB rendering for imported surfaces

If texture is imported and templ format is sRGB, use compatible sRGB format
to the imported texture format while creating surface view.

tested with MTT piglit, glretrace, viewperf and conform

Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Charmaine Lee <charmainel@vmware.com>

src/gallium/drivers/svga/svga_surface.c

@@ -305,10 +305,17 @@ svga_create_surface_view(struct pipe_context *pipe,
       bind = PIPE_BIND_RENDER_TARGET;
    }
 
-   if (tex->imported)
+   if (tex->imported) {
+      /* imported resource (a window) */
       format = tex->key.format;
-   else
+      if (util_format_is_srgb(surf_tmpl->format)) {
+         /* sRGB rendering to window */
+         format = svga_linear_to_srgb(format);
+      }
+   }
+   else {
       format = svga_translate_format(ss, surf_tmpl->format, bind);
+   }
 
    assert(format != SVGA3D_FORMAT_INVALID);