ALSA: mixer: oss: Return -ENODEV instead of -EFAULT in snd_mixer_oss_open()

When try_module_get() fails in snd_mixer_oss_open(), the owning module is
going away and the device is no longer usable, so -EFAULT ("bad address")
is the wrong error. Return -ENODEV, matching the other unavailable-device
paths in this function(the NULL card check and the NULL mixer_oss check).
This changes the errno reported to userspace on this rare race.
No other behaviour changes.

Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260707084506.718583-5-phucduc.bui@gmail.com

sound/core/oss/mixer_oss.c

diff --git a/sound/core/oss/mixer_oss.c b/sound/core/oss/mixer_oss.c
index f5bcc78..3a1dd1e 100644
--- a/sound/core/oss/mixer_oss.c
+++ b/sound/core/oss/mixer_oss.c
@@ -58,7 +58,7 @@ static int snd_mixer_oss_open(struct inode *inode, struct file *file)
 		kfree(fmixer);
 		snd_card_file_remove(card, file);
 		snd_card_unref(card);
-		return -EFAULT;
+		return -ENODEV;
 	}
 	snd_card_unref(card);
 	return 0;