ASoC: samsung: change gpiod_speaker_power and rx1950_audio from global to static variables

sparse reports
sound/soc/samsung/rx1950_uda1380.c:131:18: warning: symbol 'gpiod_speaker_power' was not declared. Should it be static?
sound/soc/samsung/rx1950_uda1380.c:231:24: warning: symbol 'rx1950_audio' was not declared. Should it be static?

Both gpiod_speaker_power and rx1950_audio are only used in rx1950_uda1380.c,
so their storage class specifiers should be static.

Fixes: 83d74e35 ("ASoC: samsung: rx1950: turn into platform driver")
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220629185345.910406-1-trix@redhat.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/samsung/rx1950_uda1380.c

@@ -128,7 +128,7 @@ static int rx1950_startup(struct snd_pcm_substream *substream)
 					&hw_rates);
 }
 
-struct gpio_desc *gpiod_speaker_power;
+static struct gpio_desc *gpiod_speaker_power;
 
 static int rx1950_spk_power(struct snd_soc_dapm_widget *w,
 				struct snd_kcontrol *kcontrol, int event)
@@ -228,7 +228,7 @@ static int rx1950_probe(struct platform_device *pdev)
 	return devm_snd_soc_register_card(dev, &rx1950_asoc);
 }
 
-struct platform_driver rx1950_audio = {
+static struct platform_driver rx1950_audio = {
 	.driver = {
 		.name = "rx1950-audio",
 		.pm = &snd_soc_pm_ops,