LU-9667 lnet: Add new structs for sysfs LND APIs

LU-9667 lnet: Add new structs for sysfs LND APIs

Adding new generic LND peer and conn structure.
These structs will be used by the sysfs APIs to
create LND sysfs structure.

Create lnd kobject and lnd peers kset in
lnet_register_lnd() and change its return type
to int to take care of error handling.

With this patch, ko2iblnd_tunables_init() and
ksocklnd_tunables_init() are changed to have
return type as void since both these functions
always return 0.

Change-Id: Ibeb9a7d2fcc9c7b12a733cf783fd57537de952c4
Test-Parameters: forbuildonly
Signed-off-by: Sonia Sharma <sonia.sharma@intel.com>
Reviewed-on: https://review.whamcloud.com/32664
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Sonia Sharma <sharmaso@whamcloud.com>