dma-coherent: remove the DMA_MEMORY_MAP and DMA_MEMORY_IO flags

DMA_MEMORY_IO was never used in the tree, so remove it.  That means there is
no need for the DMA_MEMORY_MAP flag either now, so remove it as well and
change dma_declare_coherent_memory to return a normal errno value.

Signed-off-by: Christoph Hellwig <hch@lst.de>
 Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>

drivers/base/dma-mapping.c

@@ -176,13 +176,10 @@ int dmam_declare_coherent_memory(struct device *dev, phys_addr_t phys_addr,
 
 	rc = dma_declare_coherent_memory(dev, phys_addr, device_addr, size,
 					 flags);
-	if (rc) {
+	if (!rc)
 		devres_add(dev, res);
-		rc = 0;
-	} else {
+	else
 		devres_free(res);
-		rc = -ENOMEM;
-	}
 
 	return rc;
 }