staging: vt6656: return if pControlURB->hcpriv not NULL

Fixes occasional urb submitted while active.

Even thought the fMP_CONTROL_WRITES/fMP_CONTROL_READS flags
are cleared in the return context urb->hcpriv is not NULL.

check for hcpriv and return STATUS_FAILURE if not NULL.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vt6656/usbpipe.c

@@ -118,6 +118,9 @@ int PIPEnsControlOut(struct vnt_private *pDevice, u8 byRequest, u16 wValue,
 	if (pDevice->Flags & fMP_CONTROL_READS)
 		return STATUS_FAILURE;
 
+	if (pDevice->pControlURB->hcpriv)
+		return STATUS_FAILURE;
+
 	MP_SET_FLAG(pDevice, fMP_CONTROL_WRITES);
 
 	pDevice->sUsbCtlRequest.bRequestType = 0x40;
@@ -177,6 +180,9 @@ int PIPEnsControlIn(struct vnt_private *pDevice, u8 byRequest, u16 wValue,
 	if (pDevice->Flags & fMP_CONTROL_WRITES)
 		return STATUS_FAILURE;
 
+	if (pDevice->pControlURB->hcpriv)
+		return STATUS_FAILURE;
+
 	MP_SET_FLAG(pDevice, fMP_CONTROL_READS);
 
 	pDevice->sUsbCtlRequest.bRequestType = 0xC0;