MIPS: pci-ar2315: include <linux/dma-direct.h> for phys_to_dma

Ensure this file has a prototype for phys_to_dma and dma_to_phys.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/pci/pci-ar2315.c

@@ -31,6 +31,7 @@
 #include <linux/platform_device.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/dma-direct.h>
 #include <linux/mm.h>
 #include <linux/delay.h>
 #include <linux/bitops.h>