usb: move the OTG state from the USB PHY to the OTG structure

Before using the PHY framework instead of the USB PHY one, we need to
move the OTG state into another place, since it won't be available when
USB PHY isn't used. This patch moves the OTG state into the OTG
structure, and makes all the needed modifications in the drivers
using the OTG state.

[ balbi@ti.com : fix build regressions with phy-tahvo.c, musb_dsps.c,
		phy-isp1301-omap, and chipidea's debug.c ]

Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>