leds: lp55xx: Use devm_clk_get_enabled() helpers

Simplify the code a bunch by using managed resource helpers.

Also, there is no need to save clk pointer anymore.

Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Huan Yang <link@vivo.com>
Link: https://lore.kernel.org/r/20240821013725.785956-1-link@vivo.com


Signed-off-by: Lee Jones <lee@kernel.org>