ASoC: hdmi-codec: make hdmi_codec_controls static

This symbol is not used outside of hdmi-codec.c, so marks it static.

Fix the following sparse warning:

sound/soc/codecs/hdmi-codec.c:750:25: warning: symbol
'hdmi_codec_controls' was not declared. Should it be static?
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Link: https://lore.kernel.org/r/1623822941-3077-1-git-send-email-jiapeng.chong@linux.alibaba.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/hdmi-codec.c

@@ -747,7 +747,7 @@ static const struct snd_soc_dai_ops hdmi_codec_spdif_dai_ops = {
 			 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE |\
 			 SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE)
 
-struct snd_kcontrol_new hdmi_codec_controls[] = {
+static struct snd_kcontrol_new hdmi_codec_controls[] = {
 	{
 		.access = SNDRV_CTL_ELEM_ACCESS_READ,
 		.iface = SNDRV_CTL_ELEM_IFACE_PCM,