fix: gsm0808.c: unterminated value_string array gsm0808_bssap_names

Change-Id: Ie38bae32372dc41e1902a8f6f0bc550ae515cfb8
diff --git a/src/gsm/gsm0808.c b/src/gsm/gsm0808.c
index 4035f46..de80006 100644
--- a/src/gsm/gsm0808.c
+++ b/src/gsm/gsm0808.c
@@ -540,6 +540,7 @@
 static const struct value_string gsm0808_bssap_names[] = {
 	{ BSSAP_MSG_BSS_MANAGEMENT, 		"MANAGEMENT" },
 	{ BSSAP_MSG_DTAP,			"DTAP" },
+	{ 0, NULL }
 };
 
 const char *gsm0808_bssap_name(uint8_t msg_type)