ASoC: uniphier: evea: fix lisence comment style

This patch changes lisence comment style from C to C++.
And use SPDX instead of boiler plate of GPLv2, as same as
other audio codec drivers.
Signed-off-by: Katsuhiro Suzuki <suzuki.katsuhiro@socionext.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/uniphier/evea.c

 // SPDX-License-Identifier: GPL-2.0
-/*
- * Socionext UniPhier EVEA ADC/DAC codec driver.
- *
- * Copyright (c) 2016-2017 Socionext Inc.
- *
- * 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; 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see <http://www.gnu.org/licenses/>.
- */
+//
+// Socionext UniPhier EVEA ADC/DAC codec driver.
+//
+// Copyright (c) 2016-2017 Socionext Inc.
 
 #include <linux/clk.h>
 #include <linux/module.h>