iio: gts-helper: Fix memory leaks for the error path of iio_gts_build_avail_scale_table()

If per_time_scales[i] or per_time_gains[i] kcalloc fails in the for loop
of iio_gts_build_avail_scale_table(), the err_free_out will fail to call
kfree() each time when i is reduced to 0, so all the per_time_scales[0]
and per_time_gains[0] will not be freed, which will cause memory leaks.

Fix it by checking if i >= 0.

Cc: [email protected]
Fixes: 38416c2 ("iio: light: Add gain-time-scale helpers")
Reviewed-by: Matti Vaittinen <[email protected]>
Signed-off-by: Jinjie Ruan <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jonathan Cameron <[email protected]>

Author: Jinjie Ruan

drivers/iio/industrialio-gts-helper.c

@@ -315,7 +315,7 @@ static int iio_gts_build_avail_scale_table(struct iio_gts *gts)
 	return 0;
 
 err_free_out:
-	for (i--; i; i--) {
+	for (i--; i >= 0; i--) {
 		kfree(per_time_scales[i]);
 		kfree(per_time_gains[i]);
 	}