xen/riscv: update two license headers

Updated the license header in a separate comment of its own.

Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>
Reviewed-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/riscv/include/asm/csr.h

@@ -1,6 +1,5 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
- * SPDX-License-Identifier: GPL-2.0-only
- *
  * Copyright (C) 2015 Regents of the University of California
  */
 

xen/arch/riscv/include/asm/riscv_encoding.h

@@ -1,6 +1,5 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
 /*
- * SPDX-License-Identifier: BSD-2-Clause
- *
  * Copyright (c) 2019 Western Digital Corporation or its affiliates.
  *
  * Authors: