remoteproc: imx_dsp_rproc: Correct the comment style of copyright

Change '//' on copyright line to C style comments.

Reported-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1634092749-3707-1-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

drivers/remoteproc/imx_dsp_rproc.c

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
-// Copyright 2021 NXP
+/* Copyright 2021 NXP */
 
 #include <dt-bindings/firmware/imx/rsrc.h>
 #include <linux/arm-smccc.h>