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

In the Linux kernel, the following vulnerability has been resolved:

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.