USB: host: ohci-at91: suspend: delay needed before to stop clocks

In order to completely remove marginal power consumption in PM suspend,
we need to let the controller settle down before being stopped.
In ohci_hcd_at91_drv_suspend() function, one additional delay is needed before
to stop the clocks.
Reported-by: Boris Krasnovskiy <Boris.Krasnovskiy@lairdconnect.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20190911064154.28633-3-nicolas.ferre@microchip.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ohci-at91.c

@@ -628,6 +628,7 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
 
 		/* flush the writes */
 		(void) ohci_readl (ohci, &ohci->regs->control);
+		msleep(1);
 		at91_stop_clock(ohci_at91);
 	}