hexagon: remove arch-specific dma_supported implementation

This implementation is simply bogus - hexagon only has a simple
direct mapped DMA implementation and thus doesn't care about the
address.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Richard Kuo <rkuo@codeaurora.org>

arch/hexagon/kernel/dma.c

@@ -35,15 +35,6 @@ static inline void *dma_addr_to_virt(dma_addr_t dma_addr)
 	return phys_to_virt((unsigned long) dma_addr);
 }
 
-int dma_supported(struct device *dev, u64 mask)
-{
-	if (mask == DMA_BIT_MASK(32))
-		return 1;
-	else
-		return 0;
-}
-EXPORT_SYMBOL(dma_supported);
-
 static struct gen_pool *coherent_pool;