reset: hi6220: Make reset_control_ops const

The hi6220_reset_ops structure is never modified. Make it const.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
diff --git a/drivers/reset/hisilicon/hi6220_reset.c b/drivers/reset/hisilicon/hi6220_reset.c
index 744b2e7..8f55fd4 100644
--- a/drivers/reset/hisilicon/hi6220_reset.c
+++ b/drivers/reset/hisilicon/hi6220_reset.c
@@ -57,7 +57,7 @@
 	return 0;
 }
 
-static struct reset_control_ops hi6220_reset_ops = {
+static const struct reset_control_ops hi6220_reset_ops = {
 	.assert = hi6220_reset_assert,
 	.deassert = hi6220_reset_deassert,
 };