drm/omap: plane: Remove redundant color encoding and range initialisation

The omap KMS driver will call drm_plane_create_color_properties() with
a default encoding and range values of BT601 and Full Range,
respectively.

Since the initial value wasn't carried over in the state, the driver had
to set it again in omap_plane_reset(). However, the helpers have been
adjusted to set it properly at reset, so this is not needed anymore.

Reviewed-by: Tomi Valkeinen <tomba@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220221095918.18763-23-maxime@cerno.tech