Using [SCHED_FIFO, 98] for running the responder thread will work for
both EVL and native preemption configurations (i.e. GPIO mode). On the
latter, it won't compete with high-priority housekeeping threads
running in kernel space (prio 99) which is recommended and saner. On
both, this leaves lower priority levels for common application-level
threads.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>