LU-6142 UAPI: replace cfs_size_* macros with __ALIGN_KERNEL

LU-6142 UAPI: replace cfs_size_* macros with __ALIGN_KERNEL

The lustre specific cfs_size_* macros can be easily replaced with
the __ALIGN_KERNEL macro provided by the linux kernel for our
user land code. This brings us closer to building against the
upstream client.

Change-Id: I5cd261807f60296eaac884b66f084c128adc5b01
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/30379
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Ben Evans <bevans@cray.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>