ALSA: hda - Make snd_hda_gen_spec_free() static

The last user of snd_hda_gen_spec_free() is patch_via.c, and we can
rewrite it safely with snd_hda_gen_free(), so that
snd_hda_gen_spec_free() can be a local function in hda_generic.c.

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

sound/pci/hda/hda_generic.h

@@ -296,7 +296,6 @@ struct hda_gen_spec {
 };
 
 int snd_hda_gen_spec_init(struct hda_gen_spec *spec);
-void snd_hda_gen_spec_free(struct hda_gen_spec *spec);
 
 int snd_hda_gen_init(struct hda_codec *codec);
 void snd_hda_gen_free(struct hda_codec *codec);