drm/atomic-helper: Add a TV properties reset helper

The drm_tv_create_properties() function will create a bunch of properties,
but it's up to each and every driver using that function to properly reset
the state of these properties leading to inconsistent behaviours.

Let's create a helper that will take care of it.

Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
Acked-in-principle-or-something-like-that-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v10-13-256dad125326@cerno.tech


Signed-off-by: Maxime Ripard <maxime@cerno.tech>