usb: cdns3: Fix sheduling with locks held.

Patch fix issue in cdns3_ep0_feature_handle_device function.

The function usleep_range can't be used there because this function is
called with locks held and IRQs disabled in
cdns3_device_thread_irq_handler().

To resolve this issue patch replaces usleep_range with mdelay.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Fixes: 7733f6c3

 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Link: https://lore.kernel.org/r/1569484721-4424-1-git-send-email-pawell@cadence.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>