iio: dac: ad5592r: Off by one bug in ad5592r_alloc_channels()

BugLink: https://launchpad.net/bugs/1644726

The > here should be >= or we go beyond the end for the array.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
(backported from commit 04bf0217)
Signed-off-by: Shrirang Bagul <shrirang.bagul@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/iio/dac/ad5592r-base.c

@@ -530,7 +530,7 @@ static int ad5592r_alloc_channels(struct ad5592r_state *st)
 
 	device_for_each_child_node(st->dev, child) {
 		ret = fwnode_property_read_u32(child, "reg", &reg);
-		if (ret || reg > ARRAY_SIZE(st->channel_modes))
+		if (ret || reg >= ARRAY_SIZE(st->channel_modes))
 			continue;
 
 		ret = fwnode_property_read_u32(child, "adi,mode", &tmp);