usb: chipidea: cleanup dma_pool if udc_start() fails

If udc_start() fails the qh_pool dma-pool cannot be closed because
it's still in use. This patch factors out the dma_pool_free() loop
into destroy_eps() and calls it in the error path of udc_start(),
too.

Cc: stable <stable@vger.kernel.org>
Reviewed-by: Richard Zhao <richard.zhao@freescale.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>