dmaengine: omap-dma: make omap_dma_filter_fn private

With the audio driver no longer referring to this function, it
can be made private to the dmaengine driver itself, and the
header file removed.
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/lkml/20190307151646.1016966-1-arnd@arndb.de/Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20190722081705.2084961-1-arnd@arndb.deSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/ti/omap-dma.c

@@ -202,6 +202,7 @@ static const unsigned es_bytes[] = {
 	[CSDP_DATA_TYPE_32] = 4,
 };
 
+static bool omap_dma_filter_fn(struct dma_chan *chan, void *param);
 static struct of_dma_filter_info omap_dma_info = {
 	.filter_fn = omap_dma_filter_fn,
 };
@@ -1637,7 +1638,7 @@ static struct platform_driver omap_dma_driver = {
 	},
 };
 
-bool omap_dma_filter_fn(struct dma_chan *chan, void *param)
+static bool omap_dma_filter_fn(struct dma_chan *chan, void *param)
 {
 	if (chan->device->dev->driver == &omap_dma_driver.driver) {
 		struct omap_dmadev *od = to_omap_dma_dev(chan->device);

include/linux/omap-dma.h

 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __LINUX_OMAP_DMA_H
 #define __LINUX_OMAP_DMA_H
-#include <linux/omap-dmaengine.h>
-
 /*
  *  Legacy OMAP DMA handling defines and functions
  *

include/linux/omap-dmaengine.h

-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * OMAP DMA Engine support
- */
-#ifndef __LINUX_OMAP_DMAENGINE_H
-#define __LINUX_OMAP_DMAENGINE_H
-
-struct dma_chan;
-
-#if defined(CONFIG_DMA_OMAP) || (defined(CONFIG_DMA_OMAP_MODULE) && defined(MODULE))
-bool omap_dma_filter_fn(struct dma_chan *, void *);
-#else
-static inline bool omap_dma_filter_fn(struct dma_chan *c, void *d)
-{
-	return false;
-}
-#endif
-#endif /* __LINUX_OMAP_DMAENGINE_H */