dri: Pass the __DRIscreen and the __DRIscreen private back to image lookup

We will typically have a current context when we need to lookup the image,
but the lookup implementation don't need it so drop it.

src/mesa/drivers/dri/intel/intel_fbo.c

@@ -202,8 +202,8 @@ intel_image_target_renderbuffer_storage(GLcontext *ctx,
    __DRIimage *image;
 
    screen = intel->intelScreen->driScrnPriv;
-   image = screen->dri2.image->lookupEGLImage(intel->driContext, image_handle,
-					      intel->driContext->loaderPrivate);
+   image = screen->dri2.image->lookupEGLImage(screen, image_handle,
+					      screen->loaderPrivate);
    if (image == NULL)
       return;