LU-3963 libcfs: convert DT objects atomic primitives

LU-3963 libcfs: convert DT objects atomic primitives

This patch convers all cfs_atomic primitives in
ofd, osc, osd-ldiskfs and osd-zfs to the linux
atomic api.

Signed-off-by: Liu Xuezhao <xuezhao.liu@emc.com>
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: I235cd45503115a936cf502e5469daf806cf16078
Reviewed-on: http://review.whamcloud.com/7076
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>