LU-8560 lustre: remove unused crypto handlers in lustre_compat.h

LU-8560 lustre: remove unused crypto handlers in lustre_compat.h

The unused crypto code in lustre_compat.h doesn't
build with linux kernel version 4.6+. Since its
not used just delete it.

Test-Parameters: trivial

Change-Id: If7634428357837372f4756b0ace3af9c2cd77366
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: http://review.whamcloud.com/22204
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Frank Zago <fzago@cray.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>