ASoC: SOF: amd: add conditional check for acp_clkmux_sel register

Few AMD platforms require ACP ACLK as clock source.
Add conditional check for clock mux selection register for
switching between internal clock and ACP ACLK.
Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
Link: https://lore.kernel.org/r/20230823073340.2829821-5-Vijendar.Mukunda@amd.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/amd/acp.c

@@ -423,7 +423,9 @@ static int acp_reset(struct snd_sof_dev *sdev)
 	if (ret < 0)
 		dev_err(sdev->dev, "timeout in releasing reset\n");
 
-	snd_sof_dsp_write(sdev, ACP_DSP_BAR, desc->acp_clkmux_sel, ACP_CLOCK_ACLK);
+	if (desc->acp_clkmux_sel)
+		snd_sof_dsp_write(sdev, ACP_DSP_BAR, desc->acp_clkmux_sel, ACP_CLOCK_ACLK);
+
 	if (desc->ext_intr_enb)
 		snd_sof_dsp_write(sdev, ACP_DSP_BAR, desc->ext_intr_enb, 0x01);