hwrng: exynos - remove redundant dev_err call in exynos_trng_probe()

There is a error message within devm_ioremap_resource
already, so remove the dev_err call to avoid redundant
error message.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>