staging: lustre: 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outdated info.

Signed-off-by: Alexander Zarochentsev <alexander.zarochentsev@seagate.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8418
Seagate-bug-id: MRP-2939
Reviewed-on: http://review.whamcloud.com/21440


Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>