The kqueue system call takes no arguments, hence there should be no need
to zero the registers used for the first syscall arguments.

Change-Id: Ia79b2d4f4d568bb6795cb885e1464cf1fc2bf7c7
Reviewed-on: https://go-review.googlesource.com/c/go/+/174128
Run-TryBot: Benny Siegert <bsiegert@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>