cpu: adjust godoc comment for hostByteOrder
cpu: adjust godoc comment for hostByteOrder

This was changed in CL 194646 to no longer depend on the encoding/binary
package. Adjust the godoc comment as well.

Change-Id: I1f23dc83a4c1256ebce8a283623f79e1bd00da51
Reviewed-on: https://go-review.googlesource.com/c/sys/+/238037
Run-TryBot: Tobias Klauser <0a68dd4915066ec5d3f81f75a828fee53dcc8822@gmail.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@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