drm/vc4: hdmi: Depends on CONFIG_PM

commit 72e2329e

 upstream.

We already depend on runtime PM to get the power domains and clocks for
most of the devices supported by the vc4 driver, so let's just select it
to make sure it's there.

Link: https://lore.kernel.org/r/20220629123510.1915022-38-maxime@cerno.tech
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
(cherry picked from commit f1bc386b

)
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Cc: "Sudip Mukherjee (Codethink)" <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>