The platform data bits can be inferred from the other members of
struct usbhs_phy_data. So get rid of the platform_data member.

Build the platform data for the PHY device in usbhs_init_phys() instead.
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRoger Quadros <rogerq@ti.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>