LU-16518 lnet: remove unused lnet_find_peer_net_locked()

LU-16518 lnet: remove unused lnet_find_peer_net_locked()

This function is no longer used, so let's drop it.

Fixes: 4e48761a5719 ("LU-9120 lnet: refactor lnet_select_pathway()")
Test-Parameters: trivial
Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: I71ab22793e63577f7e0fb88dfc14cddcbc32e17e
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58552
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>