unix: use correctly aligned result buffer in SysctlClockinfo
unix: use correctly aligned result buffer in SysctlClockinfo

It's not guaranteed that the []byte buffer will be aligned as
required for Clockinfo. Use a Clockinfo var for the sysctl call
instead.

This came up during the review for SysctlUvmexp on OpenBSD in CL
139278. Thanks to Ian Lance Taylor for pointing this out.

Change-Id: Idc7a624922da7249c6e7d5ce0236a431b58ebe5f
Reviewed-on: https://go-review.googlesource.com/c/139279
Run-TryBot: Tobias Klauser <0a68dd4915066ec5d3f81f75a828fee53dcc8822@gmail.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

multiplay/golang-sys,golang/sys,multiplay/golang-sys,multiplay/golang-sys,golang/sys,multiplay/golang-sys,golang/sys