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 <robert.jarzmik@free.fr>
Acked-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/pxa_dma.c

@@ -179,7 +179,7 @@ static unsigned int pxad_drcmr(unsigned int line)
 	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
@@ -1500,7 +1500,7 @@ static struct platform_driver pxad_driver = {
 	.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;
@@ -1513,7 +1513,6 @@ bool pxad_filter_fn(struct dma_chan *chan, void *param)
 
 	return true;
 }
-EXPORT_SYMBOL_GPL(pxad_filter_fn);
 
 module_platform_driver(pxad_driver);