[tests] Fix the tests... link again

diff --git a/tests/gsm0408/gsm0408_test.c b/tests/gsm0408/gsm0408_test.c
index cda28b1..c2f3f3f 100644
--- a/tests/gsm0408/gsm0408_test.c
+++ b/tests/gsm0408/gsm0408_test.c
@@ -82,3 +82,4 @@
 void msgb_alloc(void) {}
 void gsm0411_send_sms(void) {}
 void lchan_auto_release(void) {}
+void page_request_stop(void) {}