crypto: ccp - use dma_mapping_error to check map error

The return value of dma_map_single() should be checked by
dma_mapping_error(). However, in function ccp_init_dm_workarea(), its
return value is checked against NULL, which could result in failures.
Signed-off-by: Pan Bian <bianpan2016@163.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/ccp/ccp-ops.c

@@ -168,7 +168,7 @@ static int ccp_init_dm_workarea(struct ccp_dm_workarea *wa,
 
 		wa->dma.address = dma_map_single(wa->dev, wa->address, len,
 						 dir);
-		if (!wa->dma.address)
+		if (dma_mapping_error(wa->dev, wa->dma.address))
 			return -ENOMEM;
 
 		wa->dma.length = len;