usb: chipidea: udc: configure iso endpoints

This patch adds iso endpoint support to the device controller.
It makes use of the multiplication bits in the maxpacket field
of the endpoint and calculates the multiplier bits for each
transfer description on every request.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Reviewed-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>