drm/omap: hdmi4: fix use of uninitialized var

If use_mclk is false, mclk_mode is written to a register without
initialization. This doesn't cause any ill effects as the written value
is not used when use_mclk is false.

To fix this, write use_mclk only when use_mclk is true.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190930103840.18970-8-tomi.valkeinen@ti.comReviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

drivers/gpu/drm/omapdrm/dss/hdmi4_core.c

@@ -542,8 +542,9 @@ static void hdmi_core_audio_config(struct hdmi_core_data *core,
 	}
 
 	/* Set ACR clock divisor */
-	REG_FLD_MOD(av_base,
-			HDMI_CORE_AV_FREQ_SVAL, cfg->mclk_mode, 2, 0);
+	if (cfg->use_mclk)
+		REG_FLD_MOD(av_base, HDMI_CORE_AV_FREQ_SVAL,
+			    cfg->mclk_mode, 2, 0);
 
 	r = hdmi_read_reg(av_base, HDMI_CORE_AV_ACR_CTRL);
 	/*