drm/amd/display: Fix TDR eDP and USB4 display light up issue

[Why]
After TDR recovery, eDP and USB4 display does not light up. Because
dmub outbox notifications are not enabled after dmub reload and link
encoder assignments for the streams are not cleared before dc state
reset.

[How]
- Dmub outbox notification is enabled after tdr recovery by issuing
  inbox command to dmub.
- Link encoders for the streams are unassigned before dc state reset.
Reviewed-by: NJimmy Kizito <Jimmy.Kizito@amd.com>
Reviewed-by: NJun Lei <Jun.Lei@amd.com>
Acked-by: NTom Chung <chiahsuan.chung@amd.com>
Signed-off-by: NMeenakshikumar Somasundaram <meenakshikumar.somasundaram@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -4337,6 +4337,7 @@ void dc_enable_dmub_outbox(struct dc *dc)
 	struct dc_context *dc_ctx = dc->ctx;
 
 	dmub_enable_outbox_notification(dc_ctx->dmub_srv);
+	DC_LOG_DC("%s: dmub outbox notifications enabled\n", __func__);
 }
 
 /**

drivers/gpu/drm/amd/display/dc/dc_link.h

@@ -344,6 +344,7 @@ enum dc_detect_reason {
 	DETECT_REASON_HPDRX,
 	DETECT_REASON_FALLBACK,
 	DETECT_REASON_RETRAIN,
+	DETECT_REASON_TDR,
 };
 
 bool dc_link_detect(struct dc_link *dc_link, enum dc_detect_reason reason);