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>

Documentation/devicetree/bindings/usb/atmel-usb.txt

@@ -3,8 +3,10 @@ Atmel SOC USB controllers
 OHCI
 
 Required properties:
- - compatible: Should be "atmel,at91rm9200-ohci" for USB controllers
-   used in host mode.
+ - compatible: Should be one of the following
+	       "atmel,at91rm9200-ohci" for USB controllers used in host mode.
+	       "atmel,sama5d2-ohci" for USB controllers used in host mode
+	       on SAMA5D2 which can force to suspend.
  - reg: Address and length of the register set for the device
  - interrupts: Should contain ehci interrupt
  - clocks: Should reference the peripheral, host and system clocks