scsi: lpfc: Fix ancient double free

The "pmb" pointer is freed at the start of the function and then freed
again in the error handling code.

Link: https://lore.kernel.org/r/YA6E8rO51hE56SVw@mwanda


Fixes: 92d7f7b0 ("[SCSI] lpfc: NPIV: add NPIV support on top of SLI-3")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>