spi: cs42l43: Make handling missing spk-id GPIOs explicit

gpiod_get_array_optional() for spk-id GPIOs can return NULL, if they are
missing, so do not pass the value to PTR_ERR but instead explicitly
treat NULL as acceptable condition.  The old code was correct, but
misleading because PTR_ERR usually is used on errors.

Reported by Smatch:
  drivers/spi/spi-cs42l43.c:241 cs42l43_get_speaker_id_gpios() warn: passing zero to 'PTR_ERR'

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://patch.msgid.link/20250501-n-smatch-fixes-v2-2-d2ad9c1f2e67@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: krzk

drivers/spi/spi-cs42l43.c

@@ -237,7 +237,9 @@ static int cs42l43_get_speaker_id_gpios(struct cs42l43_spi *priv, int *result)
 	int i, ret;
 
 	descs = gpiod_get_array_optional(priv->dev, "spk-id", GPIOD_IN);
-	if (IS_ERR_OR_NULL(descs))
+	if (!descs)
+		return 0;
+	else if (IS_ERR(descs))
 		return PTR_ERR(descs);
 
 	spkid = 0;