arm64: don't override dma_max_pfn

The generic version now takes dma_pfn_offset into account, so there is no
more need for an architecture override.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

arch/arm64/include/asm/dma-mapping.h

@@ -76,14 +76,5 @@ static inline void dma_mark_clean(void *addr, size_t size)
 {
 }
 
-/* Override for dma_max_pfn() */
-static inline unsigned long dma_max_pfn(struct device *dev)
-{
-	dma_addr_t dma_max = (dma_addr_t)*dev->dma_mask;
-
-	return (ulong)dma_to_phys(dev, dma_max) >> PAGE_SHIFT;
-}
-#define dma_max_pfn(dev) dma_max_pfn(dev)
-
 #endif	/* __KERNEL__ */
 #endif	/* __ASM_DMA_MAPPING_H */