pwm: tegra: Don't needlessly enable and disable the clock in .remove()

There is no reason to enable the PWM clock just to assert the reset
control. (If the reset control depends on the clock this is a bug and
probably it doesn't because in .probe() the reset is deasserted without
the clock being enabled.)

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