usb: phy: Rename OTG FSM informative variables

Mark informative variables with suffix '_inf' to distinguish
them from other non-informative variables with the same name.
If such non-informative varialbes were missed, they are created.

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