USB: sa1111: add OHCI shutdown methods

Add OHCI shutdown methods to cleanly shutdown the OHCI controller on
system shutdowns and reboots.  This avoids the controller continuing
to run should be soft-reboot the platform, potentially scribbling
over system memory.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>