drm/edid: Clear EDID Deep Color Modes in drm_reset_display_info()

Even though we have the other drm_display_info fields reset, the DC
modes are missing.

This shouldn't be an issue since it's explicitly reset every time a new
EDID is parsed.

Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220125093251.594772-1-maxime@cerno.tech