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>

arch/arm/include/asm/dma-mapping.h

@@ -15,20 +15,10 @@
  * must not be used by drivers.
  */
 #ifndef __arch_page_to_dma
-
-#if !defined(CONFIG_HIGHMEM)
-static inline dma_addr_t page_to_dma(struct device *dev, struct page *page)
-{
-	return (dma_addr_t)__virt_to_bus((unsigned long)page_address(page));
-}
-#elif defined(__pfn_to_bus)
 static inline dma_addr_t page_to_dma(struct device *dev, struct page *page)
 {
 	return (dma_addr_t)__pfn_to_bus(page_to_pfn(page));
 }
-#else
-#error "this machine class needs to define __arch_page_to_dma to use HIGHMEM"
-#endif
 
 static inline void *dma_to_virt(struct device *dev, dma_addr_t addr)
 {

arch/arm/include/asm/memory.h

@@ -200,7 +200,8 @@ static inline void *phys_to_virt(unsigned long x)
 #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)