ALSA: HDA: hda_proc: Fix printf format specifier

The Pincap output had a typod format specifier, leading to an extraneous "08"
in the output, which is a reserved bit of the Vref field, and was really
confused :-).

Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>