crypto: aspeed - fix return value check in aspeed_hace_probe()

In case of error, the function devm_ioremap_resource() returns
ERR_PTR() not NULL. The NULL test in the return value check must be
replaced with IS_ERR().

Fixes: 108713a7 ("crypto: aspeed - Add HACE hash driver")
Signed-off-by: Sun Ke <sunke32@huawei.com>
Reviewed-by: Neal <Liu&lt;neal_liu@aspeedtech.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>