LU-10391 lnet: change ni_status in lnet_ni to u32*

LU-10391 lnet: change ni_status in lnet_ni to u32*

struct lnet_ni.ni_status points to a 'struct lnet_ni_status', but only
the ns_status field of that structure is ever accessed.

Change ni_status to point directly to just the ns_status field.
This will provide flexibility for introducing a variant for 'struct
lnet_ni_status' which holds a large-address nid.

Test-Parameters: trivial testlist=sanity-lnet
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: I5570608e98bc2aa1156b8d885df2a56f8ae7b6f7
Reviewed-on: https://review.whamcloud.com/44626
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Tested-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>