paride: fix off-by-one test

With `while (j++ < PX_SPIN)' j reaches PX_SPIN + 1 after the loop.  This
is probably unlikely to produce a problem.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>