Since commit fcc76072 ("pwm: bcm2835: Allow PWM driver to be used in
atomic context") struct bcm2835_pwm::dev is only assigned a value, but
it's never used. So the dev member can just be dropped.

Link: https://lore.kernel.org/r/20240129081029.2355612-2-u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>