tools headers: Synchronize prctl.h ABI header

tools headers: Synchronize prctl.h ABI header

The prctl.h ABI header was slightly updated during the development of
the interface. In particular the "immutable" parameter became a bit in
the option argument.

Synchronize prctl.h ABI header again and make use of the definition in
the testsuite and "perf bench futex".

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20250517151455.1065363-5-bigeasy@linutronix.de