futex: Validate futex value against futex size

futex: Validate futex value against futex size

Ensure the futex value fits in the given futex size. Since this adds a
constraint to an existing syscall, it might possibly change behaviour.

Currently the value would be truncated to a u32 and any high bits
would get silently lost.

Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-and-tested-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20230807123323.020870574@infradead.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>