usb: phy: fix build break

During phy interface separation from otg.h, as the enum "usb_otg_state"
was having multiple otg states info and removal of member 'state'
of this enum type from usb_phy struct did not generate any compilation
issues, I removed member state from struct usb_phy.

As this is causing build break in musb code, adding member 'state'
to usb_phy structure.

Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>