LU-10391 lnet: change lnet_del_route() to take lnet_nid

LU-10391 lnet: change lnet_del_route() to take lnet_nid

The gateway NID passed to lnet_del_route is now a struct lnet_nid.
Instead of passing LNET_NID_ANY as a wildcard, we pass
a NULL pointer.

Test-Parameters: trivial
Test-Parameters: serverversion=2.12 serverdistro=el7.9 testlist=runtests
Test-Parameters: clientversion=2.12 testlist=runtests
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I1243be20d9f40e4ac3ebc6ec5dd9bbcbae6653c3
Reviewed-on: https://review.whamcloud.com/43615
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Cyril Bordage <cbordage@whamcloud.com>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>