[SCSI] lpfc: Fix typo on NULL assignment

In the lpfc_ct_free_iocb function after freeing associated memory to the
ctiocb->context3, the ctiocb->context1 is set to NULL instead of context3.

Signed-off-by: Felipe Pena <felipensp@gmail.com>
Acked-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>