nitro_enclaves: Update copyright statement to include 2021

Update the copyright statement to include 2021, as a change has been
made over this year.

Check commit d874742f6a73 ("nitro_enclaves: Set Bus Master for the NE
PCI device") for the codebase update from this file (ne_pci_dev.c).

Reviewed-by: George-Aurelian Popescu <[e-mail]>
Signed-off-by: Andra Paraschiv <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/virt/nitro_enclaves/ne_pci_dev.c

···
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * Copyright 2020-2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
  */
 
 /**