Update to a hopefully more future proof FSF address

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/libfdt_env.h b/libfdt_env.h
index e154b8e..ee0419f 100644
--- a/libfdt_env.h
+++ b/libfdt_env.h
@@ -9,8 +9,7 @@
  * 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 to the Free Software
- * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
  *
  * Copyright IBM Corp. 2008
  * Authors: Hollis Blanchard <hollisb@us.ibm.com>