libfc: Reject PLOGI from nodes with incompatible role

Reject a PLOGI from a node with an incompatible role,
that is, initiator-to-initiator or target-to-target.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Reviewed-by: Yi Zou <yi.zou@intel.com>
Tested-by: Jack Morgan <jack.morgan@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>