drm/amd/display: check if audio clk enable is applicable

Fixing warning on dce10 with HDMI display.
Signed-off-by: Roman Li <Roman.Li@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_stream_encoder.c

@@ -720,6 +720,7 @@ static void dce110_stream_encoder_update_hdmi_info_packets(
 			const uint32_t *content =
 				(const uint32_t *) &info_frame->avi.sb[0];
 			/*we need turn on clock before programming AFMT block*/
+			if (REG(AFMT_CNTL))
 				REG_UPDATE(AFMT_CNTL, AFMT_AUDIO_CLOCK_EN, 1);
 
 			REG_WRITE(AFMT_AVI_INFO0, content[0]);