futex: Get rid of the val2 conditional dance

There is no point in checking which FUTEX operand treats the utime pointer
as 'val2' argument because that argument to do_futex() is only used by
exactly these operands.

So just handing it in unconditionally is not making any difference, but
removes a lot of pointless gunk.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210422194705.125957049@linutronix.de