ALSA: control: preserve snd_card_file_add() error code in snd_ctl_open()

snd_ctl_open() unconditionally overwrites the return value of
snd_card_file_add() with -ENODEV on failure, discarding the actual
error code.

Fix this by directly returning the original error code returned by
snd_card_file_add() (e.g. -ENOMEM or -ENODEV). This behavior is
consistent with the error handling used in other functions such as
snd_mixer_oss_open(), snd_hwdep_open(), snd_pcm_oss_open(), and others.

There is no functional change other than the returned error code in this
failure path.

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/20260708023540.6962-1-phucduc.bui@gmail.com