drm/nouveau/disp: Revert a NULL check inside nouveau_connector_get_modes

The original commit adding that check tried to protect the kenrel against
a potential invalid NULL pointer access.

However we call nouveau_connector_detect_depth once without a native_mode
set on purpose for non LVDS connectors and this broke DP support in a few
cases.

Cc: Olaf Skibbe <news@kravcenko.com>
Cc: Lyude Paul <lyude@redhat.com>
Closes: https://gitlab.freedesktop.org/drm/nouveau/-/issues/238
Closes: https://gitlab.freedesktop.org/drm/nouveau/-/issues/245
Fixes: 20a2ce87 ("drm/nouveau/dp: check for NULL nv_connector->native_mode")
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230805101813.2603989-1-kherbst@redhat.com

drivers/gpu/drm/nouveau/nouveau_connector.c

@@ -967,7 +967,7 @@ nouveau_connector_get_modes(struct drm_connector *connector)
 	/* Determine display colour depth for everything except LVDS now,
 	 * DP requires this before mode_valid() is called.
 	 */
-	if (connector->connector_type != DRM_MODE_CONNECTOR_LVDS && nv_connector->native_mode)
+	if (connector->connector_type != DRM_MODE_CONNECTOR_LVDS)
 		nouveau_connector_detect_depth(connector);
 
 	/* Find the native mode if this is a digital panel, if we didn't