iio: light: bh1745: fix information leak in triggered buffer

The 'scan' 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: eab3535 ("iio: light: ROHM BH1745 colour sensor")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://patch.msgid.link/20241125-iio_memset_scan_holes-v1-7-0cb6e98d895c@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: javiercarrascocruz

drivers/iio/light/bh1745.c

@@ -746,6 +746,8 @@ static irqreturn_t bh1745_trigger_handler(int interrupt, void *p)
 	int i;
 	int j = 0;
 
+	memset(&scan, 0, sizeof(scan));
+
 	iio_for_each_active_channel(indio_dev, i) {
 		ret = regmap_bulk_read(data->regmap, BH1745_RED_LSB + 2 * i,
 				       &value, 2);