usb: dwc3: omap: Replace deprecated API of extcon

This patch removes the deprecated notifier API of extcon framwork
and then use the new extcon API with the unique id to indicate
the each external connector (USB, USB-HOST).

Alter deprecated API as following:
- extcon_register_interest() -> extcon_register_notifier()
- extcon_get_cable_state(*edev, char *) -> extcon_get_cable_state_(*edev, id)

Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>