LU-14499 lnet: Revert "LU-13368 lnet: discard the callback"

LU-14499 lnet: Revert "LU-13368 lnet: discard the callback"

The changes introduced by LU-13368 have been shown to cause
the o2iblnd shutdown procedure to hang on lustre_rmmod
as it infinitely waits for peers to disconnect.

Those changes were also shown to cause a memory leak. Revert them.
This reverts commit babf0232273467b7199ec9a7c36047b1968913df.

HPE-bug-id: LUS-11089
Signed-off-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: I489ae4af445b18df852ec35adc958c4fac33de09
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/41937
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Frank Sehr <fsehr@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>