ARM/dma-mapping: take the bus limit into account in __dma_alloc

The DMA coherent allocator needs to take bus limits into account for
picking the zone that the memory is allocated from.

Reported-by: Roger Quadros <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>
Tested-by: Peter Ujfalusi <[e-mail]>
Tested-by: Roger Quadros <[e-mail]>

arch/arm/mm/dma-mapping.c

···
 			 gfp_t gfp, pgprot_t prot, bool is_coherent,
 			 unsigned long attrs, const void *caller)
 {
-	u64 mask = dev->coherent_dma_mask;
+	u64 mask = min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
 	struct page *page = NULL;
 	void *addr;
 	bool allowblock, cma;