crypto: ux500 - Fix error return code in hash_hw_final()

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: 8a63b199 ("crypto: ux500 - Add driver for HASH hardware")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>