Merge pull request #416 from dragos-oancea/mod_amr-nullptr-deref

[mod_amr] scan-build: Array access (from variable 'tocs') results in a null pointer dereference - switch_amr_unpack_oa()

src/mod/codecs/mod_amr/mod_amr.c

@@ -150,6 +150,9 @@ static switch_bool_t switch_amr_unpack_oa(unsigned char *buf, uint8_t *tmp, int
 	int index;
 	int framesz;
 
+	if (!buf) {
+		return SWITCH_FALSE;
+	}
 	buf++; /* CMR skip */
 	tocs = buf;
 	index = ((tocs[0]>>3) & 0xf);