crypto: aspeed - add error handling if dmam_alloc_coherent() failed

Since the acry_dev->buf_addr may be NULL, add error handling to
prevent any additional access to avoid potential issues.
Signed-off-by: Neal Liu <neal_liu@aspeedtech.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/aspeed/aspeed-acry.c

@@ -779,7 +779,10 @@ static int aspeed_acry_probe(struct platform_device *pdev)
 	acry_dev->buf_addr = dmam_alloc_coherent(dev, ASPEED_ACRY_BUFF_SIZE,
 						 &acry_dev->buf_dma_addr,
 						 GFP_KERNEL);
-	memzero_explicit(acry_dev->buf_addr, ASPEED_ACRY_BUFF_SIZE);
+	if (!acry_dev->buf_addr) {
+		rc = -ENOMEM;
+		goto err_engine_rsa_start;
+	}
 
 	aspeed_acry_register(acry_dev);