powerpc: Make logical to real cpu mapping code endian safe

powerpc: Make logical to real cpu mapping code endian safe

commit ac13282dff13cd0f4da0f0ccb134bc29bfa10255 upstream.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[jt: fixed up context due to commit 59a53afe70fd530040bdc69581f03d880157f15a
     already being backported.]
Signed-off-by: Jonathan Toppins <jtoppins@cumulusnetworks.com>
Reviewed-by: Andy Gospodarek <gospo@cumulusnetworks.com>
Acked-by: Curt Brune <curt@cumulusnetworks.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>