usb: chipidea: udc: read status of td only once in hardware_dequeue

This patch changes the read of the td status to one atomic operation to
analyse coherent bits.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
[Alex: fixed backwards endianness conversion]
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>