crypto: ixp4xx - Delete unnecessary checks before the function call "dma_pool_destroy"

The dma_pool_destroy() function tests whether its argument is NULL
and then returns immediately. Thus the test around the calls is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/ixp4xx_crypto.c

@@ -510,10 +510,8 @@ npe_error:
 	printk(KERN_ERR "%s not responding\n", npe_name(npe_c));
 	ret = -EIO;
 err:
-	if (ctx_pool)
-		dma_pool_destroy(ctx_pool);
-	if (buffer_pool)
-		dma_pool_destroy(buffer_pool);
+	dma_pool_destroy(ctx_pool);
+	dma_pool_destroy(buffer_pool);
 	npe_release(npe_c);
 	return ret;
 }