drm/i915/opregion: add intel_opregion_vbt_present() stub for ACPI=n

The opregion code needs stubs for ACPI=n. Add the missing stub for
intel_opregion_vbt_present().
Reported-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Closes: https://lore.kernel.org/r/20240312120240-afdb1b83-8517-434b-be79-06f41bafd71f@linutronix.de
Fixes: 9d9bb71f ("drm/i915: Extract opregion vbt presence check")
Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240312115757.683584-1-jani.nikula@intel.comSigned-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_opregion.h

@@ -120,6 +120,11 @@ intel_opregion_get_edid(struct intel_connector *connector)
 	return NULL;
 }
 
+static inline bool intel_opregion_vbt_present(struct drm_i915_private *i915)
+{
+	return false;
+}
+
 static inline const void *
 intel_opregion_get_vbt(struct drm_i915_private *i915, size_t *size)
 {