[SCSI] libfc: introduce LLD event callback

This patch enables LLD to listen to rport events and perform LLD
specific operations based on the rport event. This patch also stores
sp_features and spp_type in rdata for further reference by LLD.

Signed-off-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>