iio: light: as73211: Ensure buffer holes are zeroed

Given that the buffer is copied to a kfifo that ultimately user space
can read, ensure we zero it.

Fixes: 403e5586b52e ("iio: light: as73211: New driver")
Reviewed-by: Matti Vaittinen <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Cc: <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/light/as73211.c

···
 	struct {
 		__le16 chan[4];
 		aligned_s64 ts;
-	} scan;
+	} scan = { };
 	int data_result, ret;
 
 	mutex_lock(&data->mutex);