drm/amd/display: Clean up some code with unused registers

[Why]
Unused register in the code

[How]
Remove unused register
Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_hwseq.h

@@ -792,8 +792,7 @@ struct dce_hwseq_registers {
 	type D2VGA_MODE_ENABLE; \
 	type D3VGA_MODE_ENABLE; \
 	type D4VGA_MODE_ENABLE; \
-	type AZALIA_AUDIO_DTO_MODULE;\
-	type HPO_HDMISTREAMCLK_GATE_DIS;
+	type AZALIA_AUDIO_DTO_MODULE;
 
 struct dce_hwseq_shift {
 	HWSEQ_REG_FIELD_LIST(uint8_t)