PM / devfreq: exynos: Use Use devm_clk_get_enabled() helpers

PM / devfreq: exynos: Use Use devm_clk_get_enabled() helpers

The devm_clk_get_enabled() helpers:
    - call devm_clk_get()
    - call clk_prepare_enable() and register what is needed in order to
     call clk_disable_unprepare() when needed, as a managed resource.

This simplifies the code and avoids the calls to clk_disable_unprepare().

While at it, use dev_err_probe consistently, and use its return value
to return the error code.

Link: https://lore.kernel.org/lkml/20240510094034.12493-1-linux.amoon@gmail.com/
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>