drm/amd/display: make underflow status clear explicit

[why]
HUBP underflow is never cleared, which causes underflow in one
test to fail another test, violating the independence requirements

[how]
Rather than make clearing implicit, we explicitly clear underflow
status in DTN.

Signed-off-by: Jun Lei <[email protected]>
Reviewed-by: Tony Cheng <[email protected]>
Acked-by: Bhawanpreet Lakha <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
diff --git a/drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h b/drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h
index e9b702c..d6a85f4 100644
--- a/drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/hw_sequencer.h
@@ -200,6 +200,7 @@ struct hw_sequencer_funcs {
 	void (*log_hw_state)(struct dc *dc,
 		struct dc_log_buffer_ctx *log_ctx);
 	void (*get_hw_state)(struct dc *dc, char *pBuf, unsigned int bufSize, unsigned int mask);
+	void (*clear_status_bits)(struct dc *dc, unsigned int mask);
 
 	void (*wait_for_mpcc_disconnect)(struct dc *dc,
 			struct resource_pool *res_pool,