i915g: Always run in sync with the HW

src/gallium/winsys/drm/intel/gem/intel_be_batchbuffer.c

@@ -121,6 +121,10 @@ intel_be_batchbuffer_flush(struct intel_be_batchbuffer *batch,
 			debug_printf("\t%08x:    %08x\n", i*4, *ptr);
 		}
 
+		drm_intel_bo_unmap(batch->bo);
+	} else {
+		/* TODO figgure out why the gpu hangs if we don't run sync */
+		drm_intel_bo_map(batch->bo, FALSE);
 		drm_intel_bo_unmap(batch->bo);
 	}