staging/lustre: remove portals_compat25.h

staging/lustre: remove portals_compat25.h

Remove include/linux/libcfs/linux/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>
Signed-off-by: John L. Hammond <john.hammond@intel.com>
Reviewed-on: http://review.whamcloud.com/4778
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>