LU-8418 libcfs: remove lnet upcall code

LU-8418 libcfs: remove lnet upcall code

Removing lnet upcall infrastructure completely
as nobody uses it anymore. The upcall causes a delay
before calling BUG() and might even cause a hang
making getting a crash dump unreliable or containing
outdated info.

Change-Id: I20af6874116542d16bcc9a9eb75c813a124e346d
Seagate-bug-id: MRP-2939
Signed-off-by: Alexander Zarochentsev <alexander.zarochentsev@seagate.com>
Reviewed-on: http://review.whamcloud.com/21440
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>