LU-13785 lnet: Use lr_hops for avoid_asym_router_failure

LU-13785 lnet: Use lr_hops for avoid_asym_router_failure

In order for the asymmetric route failure avoidance feature to work
properly it needs to know what the hop count of a route should be.
This information is defined by the lr_hops field of the lnet_route.
The lr_single_hop is what discovery was able to determine the hop
count actually is (single or multi) based on the last ping reply.
If a remote interface on a router goes missing, the route may be
classified as multi-hop by discovery, but it should be considered
single-hop for the purposes of avoiding asymmetric route failure.

Lustre-change: https://review.whamcloud.com/39362
Lustre-commit: 2e07619477684f287a2399ccdbbde0a71289574b

HPE-bug-id: LUS-9099
Test-Parameters: trivial
Signed-off-by: Chris Horn <chris.horn@hpe.com>
Change-Id: I9c255f9a2175d964661850277808dae96ff7735c
Reviewed-on: https://review.whamcloud.com/48336
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Frank Sehr <fsehr@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>