phy: twl4030: Fix build breakage

commit e47d9254 (usb: move the OTG state
from the USB PHY to the OTG structure) moved
the OTG state field from struct usb_phy to
struct usb_otg but, even though I fixed many
other build breakages, I still missed one
on phy-twl4030-usb.c.

Fix the build breakage now.

While at that, also a build warning introduced
by the same commit.

Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>