iio: generic_buffer: Fix --trigger-num option

Initialize trig_num to -1 and handle trig_num=0 as a valid id.

Fixes: 7c7e9dad (iio: iio_generic_buffer: Add --trigger-num option)
Signed-off-by: Crestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

tools/iio/iio_generic_buffer.c

@@ -341,7 +341,7 @@ int main(int argc, char **argv)
 
 	char *data = NULL;
 	ssize_t read_size;
-	int dev_num = -1, trig_num;
+	int dev_num = -1, trig_num = -1;
 	char *buffer_access = NULL;
 	int scan_size;
 	int noevents = 0;
@@ -456,7 +456,7 @@ int main(int argc, char **argv)
 
 	if (notrigger) {
 		printf("trigger-less mode selected\n");
-	} if (trig_num > 0) {
+	} if (trig_num >= 0) {
 		char *trig_dev_name;
 		ret = asprintf(&trig_dev_name, "%strigger%d", iio_dir, trig_num);
 		if (ret < 0) {