usb: host: drop null test before destroy functions

Remove unneeded NULL test.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x;
@@

-if (x != NULL)
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);

@@
expression x;
@@

-if (x != NULL) {
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
  x = NULL;
-}
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/fotg210-hcd.c

@@ -1976,17 +1976,13 @@ static void fotg210_mem_cleanup(struct fotg210_hcd *fotg210)
 	fotg210->dummy = NULL;
 
 	/* DMA consistent memory and pools */
-	if (fotg210->qtd_pool)
-		dma_pool_destroy(fotg210->qtd_pool);
+	dma_pool_destroy(fotg210->qtd_pool);
 	fotg210->qtd_pool = NULL;
 
-	if (fotg210->qh_pool) {
-		dma_pool_destroy(fotg210->qh_pool);
-		fotg210->qh_pool = NULL;
-	}
+	dma_pool_destroy(fotg210->qh_pool);
+	fotg210->qh_pool = NULL;
 
-	if (fotg210->itd_pool)
-		dma_pool_destroy(fotg210->itd_pool);
+	dma_pool_destroy(fotg210->itd_pool);
 	fotg210->itd_pool = NULL;
 
 	if (fotg210->periodic)

drivers/usb/host/fusbh200-hcd.c

@@ -1927,17 +1927,13 @@ static void fusbh200_mem_cleanup (struct fusbh200_hcd *fusbh200)
 	fusbh200->dummy = NULL;
 
 	/* DMA consistent memory and pools */
-	if (fusbh200->qtd_pool)
-		dma_pool_destroy (fusbh200->qtd_pool);
+	dma_pool_destroy(fusbh200->qtd_pool);
 	fusbh200->qtd_pool = NULL;
 
-	if (fusbh200->qh_pool) {
-		dma_pool_destroy (fusbh200->qh_pool);
-		fusbh200->qh_pool = NULL;
-	}
+	dma_pool_destroy(fusbh200->qh_pool);
+	fusbh200->qh_pool = NULL;
 
-	if (fusbh200->itd_pool)
-		dma_pool_destroy (fusbh200->itd_pool);
+	dma_pool_destroy(fusbh200->itd_pool);
 	fusbh200->itd_pool = NULL;
 
 	if (fusbh200->periodic)