ASoC: SOF: imx: add header file for ops

Sparse (make C=2) complains about undeclared variables. Fix by adding
a real prototype instead of 'extern' in sof-of-dev.c

Signed-off-by: Pierre-Louis Bossart <[e-mail]>
Reviewed-by: Daniel Baluta <[e-mail]>
Reviewed-by: Kai Vehmanen <[e-mail]>
Reviewed-by: Paul Olaru <[e-mail]>
Signed-off-by: Peter Ujfalusi <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

sound/soc/sof/imx/imx-ops.h

···
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */
+
+#ifndef __IMX_OPS_H__
+#define __IMX_OPS_H__
+
+extern struct snd_sof_dsp_ops sof_imx8_ops;
+extern struct snd_sof_dsp_ops sof_imx8x_ops;
+extern struct snd_sof_dsp_ops sof_imx8m_ops;
+
+#endif

sound/soc/sof/imx/imx8.c

···
 #include <dt-bindings/firmware/imx/rsrc.h>
 #include "../ops.h"
 #include "imx-common.h"
+#include "imx-ops.h"
 
 /* DSP memories */
 #define IRAM_OFFSET		0x10000

sound/soc/sof/imx/imx8m.c

···
 
 #include "../ops.h"
 #include "imx-common.h"
+#include "imx-ops.h"
 
 #define MBOX_OFFSET	0x800000
 #define MBOX_SIZE	0x1000

sound/soc/sof/sof-of-dev.c

···
 #include <sound/sof.h>
 
 #include "ops.h"
-
-extern struct snd_sof_dsp_ops sof_imx8_ops;
-extern struct snd_sof_dsp_ops sof_imx8x_ops;
-extern struct snd_sof_dsp_ops sof_imx8m_ops;
+#include "imx/imx-ops.h"
 
 /* platform specific devices */
 #if IS_ENABLED(CONFIG_SND_SOC_SOF_IMX8)