LU-10391 lnet: change LNetPrimaryNID to use struct lnet_nid

LU-10391 lnet: change LNetPrimaryNID to use struct lnet_nid

Rather than taking and returning a 4-byte-addr nid, LNetPrimaryNID now
takes a pointer to a struct lnet_nid, and updates it in-place.

Test-Parameters: trivial
Test-Parameters: env=SHARED_KEY=true testlist=sanity,sanity-sec
Test-Parameters: serverversion=2.12 serverdistro=el7.9 testlist=runtests
Test-Parameters: clientversion=2.12 testlist=runtests
Change-Id: I74f193e5c533125c282f230d272a506129baa365
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Reviewed-on: https://review.whamcloud.com/43616
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Cyril Bordage <cbordage@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>