Revert "lpfc: Delete unnecessary checks before the function call mempool_destroy"

This reverts commit 9be321819c43417432a8376428b90fe3fe3a3510 which
caused a regression on hardware using the SLI3 interface.

Reported-by: Dick Kennedy <[e-mail]>
Cc: <[e-mail]> # 4.6+
Signed-off-by: Martin K. Petersen <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/lpfc/lpfc_mem.c

···
 	if (phba->lpfc_hbq_pool)
 		pci_pool_destroy(phba->lpfc_hbq_pool);
 	phba->lpfc_hbq_pool = NULL;
-	mempool_destroy(phba->rrq_pool);
+
+	if (phba->rrq_pool)
+		mempool_destroy(phba->rrq_pool);
 	phba->rrq_pool = NULL;
 
 	/* Free NLP memory pool */
 	mempool_destroy(phba->nlp_mem_pool);
 	phba->nlp_mem_pool = NULL;
-	if (phba->sli_rev == LPFC_SLI_REV4) {
+	if (phba->sli_rev == LPFC_SLI_REV4 && phba->active_rrq_pool) {
 		mempool_destroy(phba->active_rrq_pool);
 		phba->active_rrq_pool = NULL;
 	}