spi: sunplus-sp7021: Simplify clock handling with devm_clk_get_enabled()

spi: sunplus-sp7021: Simplify clock handling with devm_clk_get_enabled()

Replace devm_clk_get() followed by clk_prepare_enable() with
devm_clk_get_enabled() for the clock. This removes the need for
explicit clock enable/disable calls and the custom cleanup function,
as the managed API automatically handles clock disabling on device
removal or probe failure.

Remove the now-unnecessary sp7021_spi_disable_unprepare() function
and the devm_add_action_or_reset() call.

Signed-off-by: Pei Xiao <xiaopei01@kylinos.cn>
Link: https://patch.msgid.link/fb0bc46107975cfff4eefa9ba96fe7545996ae52.1773885292.git.xiaopei01@kylinos.cn
Signed-off-by: Mark Brown <broonie@kernel.org>