usb: phy: omap-usb2: use the new generic PHY framework

Used the generic PHY framework API to create the PHY. Now the power off and
power on are done in omap_usb_power_off and omap_usb_power_on respectively.
The omap-usb2 driver is also moved to driver/phy.

However using the old USB PHY library cannot be completely removed
because OTG is intertwined with PHY and moving to the new framework
will break OTG. Once we have a separate OTG state machine, we
can get rid of the USB PHY library.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>