LU-11893 lnet: consoldate secondary IP address handling

LU-11893 lnet: consoldate secondary IP address handling

The last piece of code with broken secondary IP address
support is lnet_parse_ip2nets(). We could fix it like
o2iblnd or socklnd was done but since the LND drivers
resolved those issues instead we can move the handling
out of the LND drivers into one place in the LNet core.
To do this we introduce struct lnet_inetdev which is
a collection of data that the current LNet layer requires.
The new function lnet_inet_enumerate() is used to collect
this information.

Change-Id: I0c532caa3cf6b2178eb1ab65e55e5883d408a185
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/34993
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Olaf Weber <olaf.weber@hpe.com>
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>