drm/i915: Prevent HW access during init from SDVO TV get_modes hook

Prevent accessing the HW from the SDVO/TV get_modes connector hook.
Returning 0 from the hook will make the caller -
drm_helper_probe_single_connector_modes() - return a default/EDID
override mode list to users. This matches the case where
intel_sdvo_get_tv_modes() fails to retrieve the current mode list due to
a HW access failure.

v2: Clarify the commit message wrt. which modes get_modes() returns. (Jouni)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240212175237.2625812-1-imre.deak@intel.com

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

@@ -2312,6 +2312,9 @@ static int intel_sdvo_get_tv_modes(struct drm_connector *connector)
 	drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s]\n",
 		    connector->base.id, connector->name);
 
+	if (!intel_display_driver_check_access(i915))
+		return 0;
+
 	/*
 	 * Read the list of supported input resolutions for the selected TV
 	 * format.