drm/i915/display/tc: Only WARN once for bogus tc port flag

No need to spam syslog/console when we can ignore/fix the flag.
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201209211828.53193-1-sean@poorly.run

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

@@ -262,7 +262,7 @@ static u32 tc_port_live_status_mask(struct intel_digital_port *dig_port)
 		mask |= BIT(TC_PORT_LEGACY);
 
 	/* The sink can be connected only in a single mode. */
-	if (!drm_WARN_ON(&i915->drm, hweight32(mask) > 1))
+	if (!drm_WARN_ON_ONCE(&i915->drm, hweight32(mask) > 1))
 		tc_port_fixup_legacy_flag(dig_port, mask);
 
 	return mask;