btrfs: replace GPL boilerplate by SPDX -- headers
Remove GPL boilerplate text (long, short, one-line) and keep the rest,
ie. personal, company or original source copyright statements. Add the
SPDX header.
Unify the include protection macros to match the file names.
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/export.h b/fs/btrfs/export.h
index 91b3908..57488ec 100644
--- a/fs/btrfs/export.h
+++ b/fs/btrfs/export.h
@@ -1,4 +1,5 @@
/* SPDX-License-Identifier: GPL-2.0 */
+
#ifndef BTRFS_EXPORT_H
#define BTRFS_EXPORT_H