[SCSI] lpfc 8.3.0 : Fix system crash due to uninitialized node access

In the IOCB completion handler, always check if the node is valid
before accessing the node object.  Added lpfc_initialize_node() to
initialize nodes.

Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>