LU-11838 lnet: getname dropping addrlen argument

LU-11838 lnet: getname dropping addrlen argument

Since kernel 4.17 ->getname() does not take int *addrlen
argument anymore, instead it's returning the length to
the caller.

Linux-commit: 9b2c45d479d0fb8647c9e83359df69162b5fbe5f

This patch is back-ported from the following one:
Lustre-commit: dbb81e826290b2db27e24a85869c9d0736726caa
Lustre-change: https://review.whamcloud.com/34672

Test-Parameters:trivial
Signed-off-by: Li Dongyang <dongyangli@ddn.com>
Change-Id: I4ad5de4a22f3fb23c07a356650ea7925acf07eed
Reviewed-by: Gu Zheng <gzheng@ddn.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/35173
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>