pwm: lpss: Only include <linux/pwm.h> where needed

Among the three files that include pwm-lpss.h only pwm-lpss.c actually
needs <linux/pwm.h>. So move the #include statement from the former to
the latter.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20250123103939.357160-2-u.kleine-koenig@baylibre.com


Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>