fpga: use SPDX

Replace GPLv2 boilerplate with SPDX in FPGA code that came from me or
from Altera.

Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/fpga/altera-hps2fpga.c b/drivers/fpga/altera-hps2fpga.c
index e4d39f0..a974d3f 100644
--- a/drivers/fpga/altera-hps2fpga.c
+++ b/drivers/fpga/altera-hps2fpga.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * FPGA to/from HPS Bridge Driver for Altera SoCFPGA Devices
  *
@@ -6,18 +7,6 @@
  * Includes this patch from the mailing list:
  *   fpga: altera-hps2fpga: fix HPS2FPGA bridge visibility to L3 masters
  *   Signed-off-by: Anatolij Gustschin <agust@denx.de>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms and conditions of the GNU General Public License,
- * version 2, as published by the Free Software Foundation.
- *
- * This program is distributed in the hope 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.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 /*