ASoC: mediatek: remove unnecessary check of clk_disable_unprepare

Because clk_disable_unprepare already checked NULL clock
parameter, so the additional checks are unnecessary, just remove them.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
Link: https://lore.kernel.org/r/20220602071809.278134-1-chi.minghao@zte.com.cn


Signed-off-by: Mark Brown <broonie@kernel.org>