usb: ohci-at91: Forcibly suspend ports while USB suspend

In order to the save power consumption, as a workaround, suspend
forcibly the USB PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI
Interrupt Configuration Register in the SFRs while OHCI USB suspend.

This suspend operation must be done before the USB clock is disabled,
resume after the USB clock is enabled.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>