virtio: clarify that ABI is usable by any implementations

We want others to implement and use virtio, so it makes sense to BSD
license the non-__KERNEL__ parts of the headers to make this crystal
clear.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Mark McLoughlin <markmc@redhat.com>
Acked-by: Ryan Harper <ryanh@us.ibm.com>
Acked-by: Eric Van Hensbergen <ericvh@gmail.com>
Acked-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/include/linux/virtio_pci.h b/include/linux/virtio_pci.h
index b315165..cdef357 100644
--- a/include/linux/virtio_pci.h
+++ b/include/linux/virtio_pci.h
@@ -9,9 +9,8 @@
  * Authors:
  *  Anthony Liguori  <aliguori@us.ibm.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.
- *
+ * This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
  */
 
 #ifndef _LINUX_VIRTIO_PCI_H