mmc: meson-gx: use devm_clk_get_enabled() for core clock

Use devm_clk_get_enabled() to simplify the code.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/b316c6ba-a373-f1d2-27d2-9add5e25a9d2@gmail.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>