gsm0808_test: Add new unit test showing dec error

This unit tests shows how decoding of such message fails. Fix will be
provided in a follow up patch to make the test pass.

Related: SYS#5891
Change-Id: Ib4ff71d5e01d464febb062c5bfe3e06ee5a19ecd
diff --git a/tests/gsm0808/gsm0808_test.ok b/tests/gsm0808/gsm0808_test.ok
index eaae7a6..8f91eb1 100644
--- a/tests/gsm0808/gsm0808_test.ok
+++ b/tests/gsm0808/gsm0808_test.ok
@@ -916,4 +916,5 @@
   Diagnostics error octet location 0 (Error location not determined)
   Diagnostics error bit location 15 (Reserved value)
   Diagnostics message that provoked the error: 00 03 25 03 25 
+Testing decoding Perform Location Report SYS#5891
 Done