phy: ralink-usb: Constify ralink_usb_phy_ops

The only usage is to pass its address to devm_phy_create() which takes a
const pointer. Make it const to allow the compiler to put it in
read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20200823220025.17588-7-rikard.falkeborn@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/ralink/phy-ralink-usb.c

@@ -142,7 +142,7 @@ static int ralink_usb_phy_power_off(struct phy *_phy)
 	return 0;
 }
 
-static struct phy_ops ralink_usb_phy_ops = {
+static const struct phy_ops ralink_usb_phy_ops = {
 	.power_on	= ralink_usb_phy_power_on,
 	.power_off	= ralink_usb_phy_power_off,
 	.owner		= THIS_MODULE,