Revert "move to hex TMSI representation"

This reverts commit 044fbe6568f82a12bf4e3addc7e3d6db529b6548.
diff --git a/openbsc/tests/gsm0408/gsm0408_test.c b/openbsc/tests/gsm0408/gsm0408_test.c
index 8ed57ca..781ef61 100644
--- a/openbsc/tests/gsm0408/gsm0408_test.c
+++ b/openbsc/tests/gsm0408/gsm0408_test.c
@@ -93,7 +93,7 @@
 	/* tmsi code */
 	mi_len = gsm48_generate_mid_from_tmsi(mi, tmsi);
 	gsm48_mi_to_string(mi_parsed, sizeof(mi_parsed), mi + 2, mi_len - 2);
-	COMPARE((uint32_t)tmsi_from_string(mi_parsed), ==, tmsi);
+	COMPARE((uint32_t)strtoul(mi_parsed, NULL, 10), ==, tmsi);
 
 	/* imsi code */
 	mi_len = gsm48_generate_mid_from_imsi(mi, imsi_odd);