mtd: lpc32xx: use typedef for dma_filter_fn

Use existing typedef for dma_filter_fn to avoid duplicating type
definition.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Acked-by: Vladimir Zapolskiy <[e-mail]>
Signed-off-by: Miquel Raynal <[e-mail]>
Link: https://lore.kernel.org/linux-mtd/[e-mail]

include/linux/mtd/lpc32xx_mlc.h

···
 #include <linux/dmaengine.h>
 
 struct lpc32xx_mlc_platform_data {
-	bool (*dma_filter)(struct dma_chan *chan, void *filter_param);
+	dma_filter_fn dma_filter;
 };
 
 #endif  /* __LINUX_MTD_LPC32XX_MLC_H */

include/linux/mtd/lpc32xx_slc.h

···
 #include <linux/dmaengine.h>
 
 struct lpc32xx_slc_platform_data {
-	bool (*dma_filter)(struct dma_chan *chan, void *filter_param);
+	dma_filter_fn dma_filter;
 };
 
 #endif  /* __LINUX_MTD_LPC32XX_SLC_H */