ocs_fc: Ignore flogi failure when the discovery is already done.

Summary:
Some targets are not responding to the FLOGI in point-to-point topology,
If the pt2pt discovery is done, Ignore the FLOGI failure.

MFC after: 3 days

Differential Revision: https://reviews.freebsd.org/D34422

(cherry picked from commit 79c56c9af583b4c6e079594b7b6ff8176e6bff7d)