scsi: lpfc: cleanup: Remove excess check on NVME io submit code path

lpfc_nvme_prep_io_cmd() checks for null pnode, but caller
lpfc_nvme_fcp_io_submit() has already ensured it's non-null.

Remove the pnode null check.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>