Generic OTG and reset support for OTG.

 - Declare and use a start_hnp() board-specific procedure.  The OMAP
   implementation will come separately, it can't yet be configured.

 - When OTG is configured, implement the usb_bus_start_enum() hook;
   that just starts a root port reset.

 - When some task (usually khubd) resets a root port, make sure it takes
   the full 50 msec.  The OHCI reset timer is in hardware, and the host
   may need to issue multiple resets to guard against concurrent resume.

 - For backward compatibility, don't kick in the new 50 msec logic unless
   it could be needed:  without CONFIG_USB_SUSPEND, nothing will suspend
   so nothing could resume.  Which is good, at least until we start to
   measure how long a reset takes ... it seems chip-specific.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>