ARM: dma-mapping: simplify page_to_dma() and __pfn_to_bus()

The non-highmem() and the __pfn_to_bus() based page_to_dma() both
compile to the same code, so its pointless having these two different
approaches.  Use the __pfn_to_bus() based version.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-By: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index e0f8f4a..9099ada 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -200,7 +200,8 @@
 #ifndef __virt_to_bus
 #define __virt_to_bus	__virt_to_phys
 #define __bus_to_virt	__phys_to_virt
-#define __pfn_to_bus(x)	((x) << PAGE_SHIFT)
+#define __pfn_to_bus(x)	__pfn_to_phys(x)
+#define __bus_to_pfn(x)	__phys_to_pfn(x)
 #endif
 
 static inline __deprecated unsigned long virt_to_bus(void *x)