LU-1346 libcfs: cleanup macros in portals_compat25.h

LU-1346 libcfs: cleanup macros in portals_compat25.h

. remove some unused/unnecessary macros such as smp_num_cpus /
  SIGNAL_MASK_ASSERT etc.

. replace some macros with direct kernel API calls such as
  RECALC_SIGPENDING/CLEAR_SIGPENDING/CURRENT_SECONDS,
  cfs_wait_event_interruptible/_exclusive etc.

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: I2fd4bb4e05136d738ee5357b35893a6ca2ec335a
Reviewed-on: http://review.whamcloud.com/4778
Tested-by: Hudson
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>