ALSA: hda: Fix NULL pointer dereference in snd_hda_ctl_add()

ALSA: hda: Fix NULL pointer dereference in snd_hda_ctl_add()

snd_hda_ctl_add() dereferences kctl->id.subdevice without checking
whether kctl is NULL. Multiple callers in sound/hda/codecs/ca0132.c
pass the return value of snd_ctl_new1() directly to snd_hda_ctl_add()
without a NULL check:

    return snd_hda_ctl_add(codec, nid, snd_ctl_new1(&knew, codec));

snd_ctl_new1() returns NULL when the underlying snd_ctl_new() fails
on memory allocation (kzalloc_flex),which can occur under memory
pressure or via fault injection.

Add a NULL check at the entry of snd_hda_ctl_add(), matching the
pattern already used by snd_ctl_add_replace() at the same call
path (sound/core/control.c:515). Return -EINVAL to let callers
handle the error gracefully.

Fixes: 44f0c9782cc6 ("ALSA: hda/ca0132: Add tuning controls")
Signed-off-by: Quan Sun <2022090917019@std.uestc.edu.cn>
Link: https://patch.msgid.link/20260514132245.3062884-1-2022090917019@std.uestc.edu.cn
Signed-off-by: Takashi Iwai <tiwai@suse.de>