generic: convert tests to SPDX license tags

Fully scripted conversion, see script in initial SPDX license commit
message.

Signed-off-by: Dave Chinner <dchinner@redhat.com>

tests/generic/406

@@ -1,4 +1,7 @@
 #! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2017 Liu Bo.  All Rights Reserved.
+#
 # FS QA Test generic/406
 #
 # If a larger dio write (size >= 128M) got splitted, the assertion in endio
@@ -7,24 +10,6 @@
 # Regression test for
 #   Btrfs: adjust outstanding_extents counter properly when dio write is split
 #
-#-----------------------------------------------------------------------
-# Copyright (c) 2017 Liu Bo.  All Rights Reserved.
-#
-# This program is free software; you can redistribute it and/or
-# modify it under the terms of the GNU General Public License as
-# published by the Free Software Foundation.
-#
-# This program is distributed in the hope that it would be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write the Free Software Foundation,
-# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
-#-----------------------------------------------------------------------
-#
-
 seq=`basename $0`
 seqres=$RESULT_DIR/$seq
 echo "QA output created by $seq"