scripts: use SPDX tag in get_maintainer and checkpatch

Add the appropriate SPDX tag to these scripts.

Miscellanea:

o Add my copyright to checkpatch

Link: http://lkml.kernel.org/r/d08e49e8f6562c58a63792aa64306d1851f81f4b.camel@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -1,9 +1,11 @@
 #!/usr/bin/env perl
+# SPDX-License-Identifier: GPL-2.0
+#
 # (c) 2001, Dave Jones. (the file handling bit)
 # (c) 2005, Joel Schopp <jschopp@austin.ibm.com> (the ugly bit)
 # (c) 2007,2008, Andy Whitcroft <apw@uk.ibm.com> (new conditions, test suite)
 # (c) 2008-2010 Andy Whitcroft <apw@canonical.com>
-# Licensed under the terms of the GNU GPL License version 2
+# (c) 2010-2018 Joe Perches <joe@perches.com>
 
 use strict;
 use warnings;

scripts/get_maintainer.pl

@@ -1,4 +1,6 @@
 #!/usr/bin/env perl
+# SPDX-License-Identifier: GPL-2.0
+#
 # (c) 2007, Joe Perches <joe@perches.com>
 #           created from checkpatch.pl
 #
@@ -7,8 +9,6 @@
 #
 # usage: perl scripts/get_maintainer.pl [OPTIONS] <patch>
 #        perl scripts/get_maintainer.pl [OPTIONS] -f <file>
-#
-# Licensed under the terms of the GNU GPL License version 2
 
 use warnings;
 use strict;