internal/cpu: add default osinit for ppc64/ppc64le
This will be used for operating systems other than AIX and Linux (both of
which provide a more specific version).
Updates #56001
Change-Id: Ia1de994866b66f03c83696faa92d0531a0b75273
Reviewed-on: https://go-review.googlesource.com/c/go/+/473698 Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Run-TryBot: Joel Sing <joel@sing.id.au> Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>