phy: freescale: imx8mq-usb: add support for imx8mp usb phy

Add initial support for imx8mp usb phy support, imx8mp usb has
a silimar phy as imx8mq, which has some different customizations
on clock and low power design when SoC integration.

Signed-off-by: Li Jun <jun.li@nxp.com>
Link: https://lore.kernel.org/r/1598276014-2377-2-git-send-email-jun.li@nxp.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>