Revert "usb: host: ehci: Use dma_pool_zalloc()"

This reverts commit 22072e83 as it is
broken.

Alan writes:
	What you can't see just from reading the patch is that in both
	cases (ehci->itd_pool and ehci->sitd_pool) there are two
	allocation paths -- the two branches of an "if" statement -- and
	only one of the paths calls dma_pool_[z]alloc.  However, the
	memset is needed for both paths, and so it can't be eliminated.
	Given that it must be present, there's no advantage to calling
	dma_pool_zalloc rather than dma_pool_alloc.
Reported-by: Erick Cafferata <erick@cafferata.me>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-mem.c

@@ -73,9 +73,10 @@ static struct ehci_qh *ehci_qh_alloc (struct ehci_hcd *ehci, gfp_t flags)
 	if (!qh)
 		goto done;
 	qh->hw = (struct ehci_qh_hw *)
-		dma_pool_zalloc(ehci->qh_pool, flags, &dma);
+		dma_pool_alloc(ehci->qh_pool, flags, &dma);
 	if (!qh->hw)
 		goto fail;
+	memset(qh->hw, 0, sizeof *qh->hw);
 	qh->qh_dma = dma;
 	// INIT_LIST_HEAD (&qh->qh_list);
 	INIT_LIST_HEAD (&qh->qtd_list);

drivers/usb/host/ehci-sched.c

@@ -1287,7 +1287,7 @@ itd_urb_transaction(
 		} else {
  alloc_itd:
 			spin_unlock_irqrestore(&ehci->lock, flags);
-			itd = dma_pool_zalloc(ehci->itd_pool, mem_flags,
+			itd = dma_pool_alloc(ehci->itd_pool, mem_flags,
 					&itd_dma);
 			spin_lock_irqsave(&ehci->lock, flags);
 			if (!itd) {
@@ -1297,6 +1297,7 @@ itd_urb_transaction(
 			}
 		}
 
+		memset(itd, 0, sizeof(*itd));
 		itd->itd_dma = itd_dma;
 		itd->frame = NO_FRAME;
 		list_add(&itd->itd_list, &sched->td_list);
@@ -2080,7 +2081,7 @@ sitd_urb_transaction(
 		} else {
  alloc_sitd:
 			spin_unlock_irqrestore(&ehci->lock, flags);
-			sitd = dma_pool_zalloc(ehci->sitd_pool, mem_flags,
+			sitd = dma_pool_alloc(ehci->sitd_pool, mem_flags,
 					&sitd_dma);
 			spin_lock_irqsave(&ehci->lock, flags);
 			if (!sitd) {
@@ -2090,6 +2091,7 @@ sitd_urb_transaction(
 			}
 		}
 
+		memset(sitd, 0, sizeof(*sitd));
 		sitd->sitd_dma = sitd_dma;
 		sitd->frame = NO_FRAME;
 		list_add(&sitd->sitd_list, &iso_sched->td_list);