LU-15462 gnilnd: Fix syntax accessor to nid_addr

LU-15462 gnilnd: Fix syntax accessor to nid_addr

Minor typo breaking build of gnilnd

Test-Parameters: trivial
Fixes: 57c03f307075 ("LU-10391 lnet: extend nids in struct lnet_msg")
Signed-off-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Change-Id: Ia8444d541c5ec175eacb2bf96d72e4b0fd80d19f
Reviewed-on: https://review.whamcloud.com/46226
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>