shell: prevent overflow of IDs

source/shell/buzzer.c

@@ -26,7 +26,7 @@ int shell_buzzer(struct console *con, size_t argc, const char **argv)
 
 	fprintf(con->fp, "%u %d %u\n", buzzer_id, state, freq);
 
-	if (buzzer_id > nbuzzers) {
+	if (buzzer_id >= nbuzzers) {
 		fprintf(con->fp, "error: invalid buzzer ID %d\n", buzzer_id);
 		return -1;
 	}

source/shell/led.c

@@ -21,7 +21,7 @@ int shell_led(struct console *con, size_t argc, const char **argv)
 	if (argc >= 1)
 		led_id = strtoul(argv[0], NULL, 0);
 
-	if (led_id > nleds) {
+	if (led_id >= nleds) {
 		fprintf(con->fp, "error: unknown LED ID %d\n", led_id);
 		return -1;
 	}