drm/i915/bios: Use the platform's port_mask when there is no VBT

When we have no VBT we currently assume ports A-F are
all pontially valid for every platform. That is nonsense.
Grab the bitmask of valid ports from the runtime info
instead.

Although the defaults we actually fill here look semi-sensible
only for hsw-skl era hardware. Dunno if we should try to do
something more appropriate here for other platforms,
or just try to nuke the whole thing?
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240319092443.15769-2-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_bios.c

@@ -2890,9 +2890,8 @@ init_vbt_panel_defaults(struct intel_panel *panel)
 static void
 init_vbt_missing_defaults(struct drm_i915_private *i915)
 {
+	unsigned int ports = DISPLAY_RUNTIME_INFO(i915)->port_mask;
 	enum port port;
-	int ports = BIT(PORT_A) | BIT(PORT_B) | BIT(PORT_C) |
-		    BIT(PORT_D) | BIT(PORT_E) | BIT(PORT_F);
 
 	if (!HAS_DDI(i915) && !IS_CHERRYVIEW(i915))
 		return;