ALSA: ctxfi - Remove useless initializations and cast

Remove useless variable initializations and cast at the beginning of
functions.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/ctxfi/ctimap.c b/sound/pci/ctxfi/ctimap.c
index d34eacd..0b73368 100644
--- a/sound/pci/ctxfi/ctimap.c
+++ b/sound/pci/ctxfi/ctimap.c
@@ -99,8 +99,8 @@
 
 void free_input_mapper_list(struct list_head *head)
 {
-	struct imapper *entry = NULL;
-	struct list_head *pos = NULL;
+	struct imapper *entry;
+	struct list_head *pos;
 
 	while (!list_empty(head)) {
 		pos = head->next;