reset: socfpga: Make reset_control_ops const

The socfpga_reset_ops structure is never modified. Make it const.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/reset/reset-socfpga.c

@@ -90,7 +90,7 @@ static int socfpga_reset_status(struct reset_controller_dev *rcdev,
 	return !(reg & BIT(offset));
 }
 
-static struct reset_control_ops socfpga_reset_ops = {
+static const struct reset_control_ops socfpga_reset_ops = {
 	.assert		= socfpga_reset_assert,
 	.deassert	= socfpga_reset_deassert,
 	.status		= socfpga_reset_status,