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>