ALSA: hda/conexant: Fix missing error check for jack detection

ALSA: hda/conexant: Fix missing error check for jack detection

In cx_probe(), the return value of snd_hda_jack_detect_enable_callback()
is ignored. This function returns a pointer, and if it fails (e.g., due
to memory allocation failure), it returns an error pointer which must
be checked using IS_ERR().

If the registration fails, the driver continues to probe, but the jack
detection callback will not be registered. This can lead to a kernel
crash later when the driver attempts to handle jack events or accesses
the uninitialized structure.

Check the return value using IS_ERR() and propagate the error via
PTR_ERR() to the probe caller.

Fixes: 7aeb25908648 ("ALSA: hda/conexant: Fix headset auto detect fail in cx8070 and SN6140")
Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
Link: https://patch.msgid.link/20260428080450.108801-1-wangdich9700@163.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>