phy: ti: usb2: Add support for AM654 USB2 PHY

Add support for the USB2 PHY on the AM654 SoC.

Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>