ALSA: hda/via: Avoid potential array out-of-bound in add_secret_dac_path()

ALSA: hda/via: Avoid potential array out-of-bound in add_secret_dac_path()

snd_hda_get_connections() can return a negative error code.
It may lead to accessing 'conn' array at a negative index.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Artemii Karasev <karasev@ispras.ru>
Fixes: 30b4503378c9 ("ALSA: hda - Expose secret DAC-AA connection of some VIA codecs")
Link: https://lore.kernel.org/r/20230119082259.3634-1-karasev@ispras.ru
Signed-off-by: Takashi Iwai <tiwai@suse.de>