LU-14195 libcfs: test for nla_strscpy

LU-14195 libcfs: test for nla_strscpy

During the development of the Linux 5.10 kernel the function
nla_strlcpy() was replaced by nla_strscpy(). Handle this
change for Lustre.

Test-parameters: trivial
Change-Id: I47f12add619cfd88a3692f0760b8bcc35b7877d9
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/46876
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>