usb: chipidea: add sys inputs for OTG fsm input

This patch adds sys input to control and show OTG fsm inputs by application,
user can do host and preipheral role switch by change these inputs.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Li Jun <b47624@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>