pwm: crc: Use consistent variable naming for driver data

All but one local variable of type pointer to struct crystalcove_pwm are
called "crc_pwm", the one outlier is called "pwm" which is usually
reserved for variables of type pointer to struct pwm_device.

So rename that one "pwm" to "crc_pwm" for consistency.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>