[intel] all flushing in intelEmitCopyBlit

Add both MI_FLUSH and intel_batchbuffer_flush to intelEmitCopyBlit.
This ensures that the data are flushed *and* the gem kernel driver sees the
various memory domain transitions.

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

@@ -375,6 +375,10 @@ intelEmitCopyBlit(struct intel_context *intel,
 		src_offset + src_y * src_pitch);
       ADVANCE_BATCH();
    }
+   BEGIN_BATCH(1, NO_LOOP_CLIPRECTS);
+   OUT_BATCH(MI_FLUSH);
+   ADVANCE_BATCH();
+   intel_batchbuffer_flush(intel->batch);
 }