dispatch: Mark swapped dispatch as _X_COLD

This touches everything that ends up in the Xorg binary; the big missing
part is GLX since that's all generated code. Cuts about 14k from the
binary on amd64.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

Xi/allowev.c

@@ -69,7 +69,7 @@ SOFTWARE.
  *
  */
 
-int
+int _X_COLD
 SProcXAllowDeviceEvents(ClientPtr client)
 {
     REQUEST(xAllowDeviceEventsReq);