ALSA: spi: Drop NULL check for snd_ctl_remove()

Since snd_ctl_remove() accepts the NULL kcontrol argument now, we can
drop the check in the caller side.

Link: https://lore.kernel.org/20240617100529.6667-6-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/spi/at73c213.c

@@ -726,12 +726,8 @@ static int snd_at73c213_mixer(struct snd_at73c213 *chip)
 	return 0;
 
 cleanup:
-	for (idx = 1; idx < ARRAY_SIZE(snd_at73c213_controls) + 1; idx++) {
-		struct snd_kcontrol *kctl;
-		kctl = snd_ctl_find_numid(card, idx);
-		if (kctl)
-			snd_ctl_remove(card, kctl);
-	}
+	for (idx = 1; idx < ARRAY_SIZE(snd_at73c213_controls) + 1; idx++)
+		snd_ctl_remove(card, snd_ctl_find_numid(card, idx));
 	return errval;
 }