ALSA: hda - Fix oops caused by recent commit "Fix internal mic for Lenovo Ideapad U300s"

Make sure we don't dereference the "quirk" pointer when it is null.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid Henningsson <david.henningsson@canonical.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_conexant.c

@@ -4441,7 +4441,9 @@ static void apply_fixup(struct hda_codec *codec,
 	struct conexant_spec *spec = codec->spec;
 
 	quirk = snd_pci_quirk_lookup(codec->bus->pci, quirk);
-	if (quirk && table[quirk->value]) {
+	if (!quirk)
+		return;
+	if (table[quirk->value]) {
 		snd_printdd(KERN_INFO "hda_codec: applying pincfg for %s\n",
 			    quirk->name);
 		apply_pincfg(codec, table[quirk->value]);