Bugfix: antminer: Avoid NULL dereference for non-BM1382/4 devices

driver-antminer.c

@@ -49,7 +49,7 @@ static const char *bm1382_chips[] = {
 
 static bool antminer_chip_has_bm1382_freq_register(const char * const prodstr)
 {
-	for (const char **chipname = bm1382_chips; chipname; ++chipname) {
+	for (const char **chipname = bm1382_chips; *chipname; ++chipname) {
 		if (strstr(prodstr, *chipname)) {
 			return true;
 		}