Increasing the values returned by the sched_get_priority_max() wrapper
above the glibc limit breaks the basic assumption that such value
could be used with pthread_create(), which is wrong.

When an overlap exist for some scheduling policies (i.e. SCHED_FIFO,
RR) between Cobalt and glibc interface, we must differentiate calls
for obtaining the static range complying with the glibc, from those
for dealing specifically with those policies if Cobalt extends them.

This translates to:

sched_get_priority_max(SCHED_FIFO/RR) => 99
sched_get_priority_max_ex(SCHED_FIFO/RR) => 256