virtio_pci: update file descriptions and copyright

There's been a lot of changes since 2007.
List main authors, add Red Hat copyright.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
index c3393d4..d3b0a78 100644
--- a/drivers/virtio/virtio_pci_legacy.c
+++ b/drivers/virtio/virtio_pci_legacy.c
@@ -1,13 +1,16 @@
 /*
- * Virtio PCI driver
+ * Virtio PCI driver - legacy device support
  *
  * This module allows virtio devices to be used over a virtual PCI device.
  * This can be used with QEMU based VMMs like KVM or Xen.
  *
  * Copyright IBM Corp. 2007
+ * Copyright Red Hat, Inc. 2014
  *
  * Authors:
  *  Anthony Liguori  <aliguori@us.ibm.com>
+ *  Rusty Russell <rusty@rustcorp.com.au>
+ *  Michael S. Tsirkin <mst@redhat.com>
  *
  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  * See the COPYING file in the top-level directory.