UnloadSubModule(): accept pointer value '1' and ignore it.

Some driver modules try to unload submodules that are now built-in.

Signed-off-by: Matthieu Herrb <matthieu.herrb@laas.fr>
Reviewed-by: Julien Cristau <jcristau@debian.org>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

hw/xfree86/loader/loadmod.c

@@ -1090,6 +1090,9 @@ UnloadSubModule(pointer _mod)
 {
     ModuleDescPtr mod = (ModuleDescPtr)_mod;
 
+    /* Some drivers are calling us on built-in submodules, ignore them */
+    if (mod == (ModuleDescPtr)1)
+	return;
     RemoveChild(mod);
     UnloadModuleOrDriver(mod);
 }