FS-11903: Fix errors reported by PVS-Studio Static Code Analyzer for switch_nat.c

src/switch_nat.c

@@ -295,7 +295,7 @@ static void *SWITCH_THREAD_FUNC switch_nat_multicast_runtime(switch_thread_t * t
 
 		if (nat_globals.nat_type == SWITCH_NAT_TYPE_UPNP) {
 			/* look for our desc URL and servicetype in the packet */
-			if (strstr(buf, nat_globals.descURL) && (buf == NULL || strstr(buf, nat_globals.data.servicetype))) {
+			if (strstr(buf, nat_globals.descURL) && strstr(buf, nat_globals.data.servicetype)) {
 				if ((pos = strstr(buf, "NTS:"))) {
 					pos = pos + 4;
 					while (*pos && *pos == ' ') {