scsi: lpfc: prevent potential null pointer dereference

Null check at line 966: if (ndlp) {, implies that ndlp might be NULL.
Functions lpfc_nlp_set_state() and lpfc_issue_els_prli() dereference
pointer ndlp. Include these function calls inside the IF block that
tests pointer ndlp.

Addresses-Coverity-ID: 1401856
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Acked-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>