Various Makefiles: Add SPDX-License-Identifier tags

After consulting with some of the SPDX team, the conclusion is that
Makefiles are worth adding SPDX-License-Identifier tags too, and most of
ours have one.  This adds tags to ones that lack them and converts a few
that had full (or in one case, very partial) license blobs into the
equivalent tag.

Cc: Kate Stewart <kstewart@linuxfoundation.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/atmark-techno/armadillo-800eva/Makefile b/board/atmark-techno/armadillo-800eva/Makefile
index 2743809..97342a8 100644
--- a/board/atmark-techno/armadillo-800eva/Makefile
+++ b/board/atmark-techno/armadillo-800eva/Makefile
@@ -1,20 +1,8 @@
 #
 # Copyright (C) 2012  Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
 #
-# 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; either version 2 of
-# the License.
-#
-# This program is distributed in the hope that it will 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.
+# SPDX-License-Identifier:	GPL-2.0
 #
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
-# MA 02111-1307 USA
 
 obj-y	+= armadillo-800eva.o