iio: adc: rockchip_saradc: fix information leak in triggered buffer

The 'data' local struct is used to push data to user space from a
triggered buffer, but it does not set values for inactive channels, as
it only uses iio_for_each_active_channel() to assign new values.

Initialize the struct to zero before using it to avoid pushing
uninitialized information to userspace.

Cc: stable@vger.kernel.org
Fixes: 4e130dc ("iio: adc: rockchip_saradc: Add support iio buffers")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://patch.msgid.link/20241125-iio_memset_scan_holes-v1-4-0cb6e98d895c@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: javiercarrascocruz

drivers/iio/adc/rockchip_saradc.c

@@ -368,6 +368,8 @@ static irqreturn_t rockchip_saradc_trigger_handler(int irq, void *p)
 	int ret;
 	int i, j = 0;
 
+	memset(&data, 0, sizeof(data));
+
 	mutex_lock(&info->lock);
 
 	iio_for_each_active_channel(i_dev, i) {