misc: cros_ec: Staticize and constify driver ops

Set the ops structure as static const. The structure is not accessible
from outside of this driver and is not going to be modified at runtime.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Quentin Schulz <quentin.schulz@cherry.de>

drivers/misc/cros_ec_sandbox.c

@@ -726,7 +726,7 @@ int cros_ec_probe(struct udevice *dev)
 	return cros_ec_register(dev);
 }
 
-struct dm_cros_ec_ops cros_ec_ops = {
+static const struct dm_cros_ec_ops cros_ec_ops = {
 	.packet = cros_ec_sandbox_packet,
 	.get_switches = cros_ec_sandbox_get_switches,
 };