cpu: remove encoding/binary dependency
cpu: remove encoding/binary dependency

It's unnecessarily heavy, bringing in reflect, etc.

I'd like for this package to become a leaf package with no
dependencies so we can use it from the Go runtime directly and remove
internal/cpu.

Change-Id: I1794854add9ad87cc13b685bae4a039e1449c22d
Reviewed-on: https://go-review.googlesource.com/c/sys/+/194646
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Martin Möhrmann <9c82b83f348009b39856043bb9ed3ef41e171aeb@google.com>

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