ALSA: hda - Add missing NULL check in amp hash allocation

Added the missing NULL check from allocator in get_alloc_hash().
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_codec.c

@@ -899,6 +899,8 @@ static struct hda_cache_head  *get_alloc_hash(struct hda_cache_rec *cache,
 
 	/* add a new hash entry */
 	info = snd_array_new(&cache->buf);
+	if (!info)
+		return NULL;
 	info->key = key;
 	info->val = 0;
 	info->next = cache->hash[idx];