fabrics: Relax match on well known disc ctrl lookup

fabrics: Relax match on well known disc ctrl lookup

In case nvmf_add_ctrl() is called to add a well known discovery
controller we also need to verify if we should ignore it (see --context
command line argument of nvme-cli). Though we have to be careful not to
overmatch on the lookup.

That means the host_traddr and host_iface might be different for the
discovery controller than the normal controllers. For example this can
happen when the discovery controller is reached via different interface
than the data controllers.

Thus only consider the transport type, target address and trsvcid only
when looking up well known discovery controllers.

Signed-off-by: Daniel Wagner <dwagner@suse.de>