MIPS: bmips: 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>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/bmips/dma.c

@@ -10,7 +10,7 @@
 
 #include <linux/device.h>
 #include <linux/dma-direction.h>
-#include <linux/dma-mapping.h>
+#include <linux/dma-direct.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/of.h>