iio: dac: ad3552r: use = { } instead of memset()

Use { } instead of memset() to zero-initialize stack memory to simplify
the code.

Signed-off-by: David Lechner <[e-mail]>
Reviewed-by: Nuno Sá <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Link: https://patch.msgid.link/202506[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/dac/ad3552r.c

···
 	struct iio_buffer *buf = indio_dev->buffer;
 	struct ad3552r_desc *dac = iio_priv(indio_dev);
 	/* Maximum size of a scan */
-	u8 buff[AD3552R_MAX_CH * AD3552R_MAX_REG_SIZE];
+	u8 buff[AD3552R_MAX_CH * AD3552R_MAX_REG_SIZE] = { };
 	int err;
 
-	memset(buff, 0, sizeof(buff));
 	err = iio_pop_from_buffer(buf, buff);
 	if (err)
 		goto end;