llc: Add move_and_merge method to llc_queue

This methods takes all LLC frames from the old LLC queue and moves
them into the current. If both queues are ordered chronologically
(recv_time), the resulting queue is also ordered.

Sponsored-by: On-Waves ehf
diff --git a/tests/llc/LlcTest.ok b/tests/llc/LlcTest.ok
index 8a5f235..311f37c 100644
--- a/tests/llc/LlcTest.ok
+++ b/tests/llc/LlcTest.ok
@@ -2,3 +2,5 @@
 === end test_llc_queue ===
 === start test_llc_meta ===
 === end test_llc_meta ===
+=== start test_llc_merge ===
+=== end test_llc_merge ===