dmaengine: pxa: make the filter function internal

As the pxa architecture and all its related drivers do not rely anymore
on the filter function, thanks to the slave map conversion, make
pxad_filter_fn() static, and remove it from the global namespace.

Signed-off-by: Robert Jarzmik <[e-mail]>
Acked-by: Vinod Koul <[e-mail]>

drivers/dma/pxa_dma.c

···
 	return 0x1000 + line * 4;
 }
 
-bool pxad_filter_fn(struct dma_chan *chan, void *param);
+static bool pxad_filter_fn(struct dma_chan *chan, void *param);
 
 /*
  * Debug fs
···
 	.remove		= pxad_remove,
 };
 
-bool pxad_filter_fn(struct dma_chan *chan, void *param)
+static bool pxad_filter_fn(struct dma_chan *chan, void *param)
 {
 	struct pxad_chan *c = to_pxad_chan(chan);
 	struct pxad_param *p = param;
···
 
 	return true;
 }
-EXPORT_SYMBOL_GPL(pxad_filter_fn);
 
 module_platform_driver(pxad_driver);
 

include/linux/dma/pxa-dma.h

···
 	enum pxad_chan_prio prio;
 };
 
-struct dma_chan;
-
-#ifdef CONFIG_PXA_DMA
-bool pxad_filter_fn(struct dma_chan *chan, void *param);
-#else
-static inline bool pxad_filter_fn(struct dma_chan *chan, void *param)
-{
-	return false;
-}
-#endif
-
 #endif /* _PXA_DMA_H_ */