LU-6387 build: add support for power8

Expand lustre to natively support the little endian Power8
platform. The architecture is reported as powerpc64le so
add that support to lustre-build-linux.m4. For the Ubuntu
packaging the platform is reported as ppc64el so include
that to the debian build configuration.

Change-Id: I506fd7228579fe1bd6e5c9e9d39db6ca06e4768d
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Reviewed-on: http://review.whamcloud.com/14115


Tested-by: Maloo <hpdd-maloo@intel.com>
Tested-by: Jenkins
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Brian J. Murrell <brian.murrell@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>