phy: fsl-imx8mq-usb: Constify imx8mp_usb_phy_ops

The only usage of imx8mp_usb_phy_ops is to assign its address to the
data field in the of_device_id struct, which is a const void 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/20200926205844.34218-1-rikard.falkeborn@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/freescale/phy-fsl-imx8mq-usb.c

@@ -131,7 +131,7 @@ static const struct phy_ops imx8mq_usb_phy_ops = {
 	.owner		= THIS_MODULE,
 };
 
-static struct phy_ops imx8mp_usb_phy_ops = {
+static const struct phy_ops imx8mp_usb_phy_ops = {
 	.init		= imx8mp_usb_phy_init,
 	.power_on	= imx8mq_phy_power_on,
 	.power_off	= imx8mq_phy_power_off,