pwm: twl-led: Drop driver local locking

pwm: twl-led: Drop driver local locking

The pwm core already serializes .apply(). twl6030's .request() and .free()
are also already serialized against .apply() because there is only a single
PWM. So the mutex doesn't add any additional protection and can be dropped.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/c1c7f646190f7cb2fe43b10959aa8dade80cb79e.1750788649.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>