drm/i915/dp: Don't WARN on failed link-retrain modeset

After a bad link state is detected, the sink capabilities with which the
link was originally trained could have changed: for instance another
sink got connected or the retraining was forced after the rate/lane count
got decreased (as a fallback). In these cases the retraining modeset
fails as expected also printing a debug message, so don't WARN on it.
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240712135724.660399-3-imre.deak@intel.com

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

@@ -5282,14 +5282,11 @@ static int intel_dp_retrain_link(struct intel_encoder *encoder,
 
 void intel_dp_link_check(struct intel_encoder *encoder)
 {
-	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
 	struct drm_modeset_acquire_ctx ctx;
 	int ret;
 
 	intel_modeset_lock_ctx_retry(&ctx, NULL, 0, ret)
 		ret = intel_dp_retrain_link(encoder, &ctx);
-
-	drm_WARN_ON(&i915->drm, ret);
 }
 
 void intel_dp_check_link_state(struct intel_dp *intel_dp)