PPC: Fix right shift by 32 bits #10870

Backported from:

    commit 4bd58c17
    Author: Erik de Castro Lopo <erikd@mega-nerd.com>
    Date:   Sun Sep 13 18:57:40 2015 +1000

    PPC: Fix right shift by 32 bits #10870

The patch in HEAD didn't apply cleanly because of the powerpc64el
work that has been done in HEAD.