usb: renesas_usbhs: add autonomy mode

Current renesas_usbhs was designed to save power when USB is not connected.
And it assumed platform uses callback to notify connection/disconnection
by external interrupt.

But some SuperH / platform board doesn't have such feature.

This patch adds autonomy mode which detect USB connection/disconnection
by internal interrupt.
But power will be always ON when autonomy mode is selected.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>