ALSA: ad1816a: Fix potential NULL pointer deref in snd_card_ad1816a_pnp()

Use pr_warn() instead of dev_warn() when 'pdev' is NULL to avoid a
potential NULL pointer dereference.

Cc: stable@vger.kernel.org
Fixes: 20869176 ("ALSA: ad1816a: Use standard print API")
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Link: https://patch.msgid.link/20250703200616.304309-2-thorsten.blum@linux.dev


Signed-off-by: Takashi Iwai <tiwai@suse.de>