hwrng: exynos - Use devm_clk_get_enabled() to get the clock

hwrng: exynos - Use devm_clk_get_enabled() to get the clock

Use devm_clk_get_enabled() helper instead of calling devm_clk_get() and
then clk_prepare_enable(). It simplifies the error handling and makes
the code more compact. Also use dev_err_probe() to handle possible
-EPROBE_DEFER errors if the clock is not available yet.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>