drm/i915: Use intel_panel_edid_fixed_mode() for sdvo

drm/i915: Use intel_panel_edid_fixed_mode() for sdvo

Despite the name intel_panel_edid_fixed_mode() doesn't actually
look in the EDID. All it does is dig out the preferred mode from
the connector's probed_modes list. That is also what the SDVO
LVDS code is doing by hand. Let's just call
intel_panel_edid_fixed_mode().

The slight difference in behaviour is that the SDVO code currently
bails if it can't find the preferred mode, whereas
intel_panel_edid_fixed_mode() will fall back to just returning
the first mode from the probed_modes list. Can't imagine why
such an LVDS panel would even exist, and also why would you have
a panel and be expected to not use it? So I'm going to assume
this is a total non-issue.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323182935.4701-9-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>