media: ir-rx51: Switch to atomic PWM API

Remove legacy PWM interface (pwm_config, pwm_enable, pwm_disable) and
replace it for the atomic PWM API.

Signed-off-by: Maíra Canal <maira.canal@usp.br>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>