usb: phy: Pass OTG FSM pointer to callback functions

struct otg_fsm may be embedded to device's context structure.
The callbacks may require pointer to struct otg_fsm to obtain
necessary data for its operation (example: regulator reference
for drv_vbus()).

Signed-off-by: Anton Tikhomirov <av.tikhomirov@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>