ALSA: ctxfi - Simple code clean up

- replace NULL == xxx with !xxx
- replace NULL != xxx with xxx
- similar trivial cleanups

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/ctxfi/ctsrc.c b/sound/pci/ctxfi/ctsrc.c
index df43a5c..c749fa7 100644
--- a/sound/pci/ctxfi/ctsrc.c
+++ b/sound/pci/ctxfi/ctsrc.c
@@ -441,7 +441,7 @@
 	else
 		src = kzalloc(sizeof(*src), GFP_KERNEL);
 
-	if (NULL == src) {
+	if (!src) {
 		err = -ENOMEM;
 		goto error1;
 	}
@@ -550,7 +550,7 @@
 
 	*rsrc_mgr = NULL;
 	src_mgr = kzalloc(sizeof(*src_mgr), GFP_KERNEL);
-	if (NULL == src_mgr)
+	if (!src_mgr)
 		return -ENOMEM;
 
 	err = rsc_mgr_init(&src_mgr->mgr, SRC, SRC_RESOURCE_NUM, hw);
@@ -679,7 +679,7 @@
 	/* Reserve memory for imapper nodes */
 	srcimp->imappers = kzalloc(sizeof(struct imapper)*desc->msr,
 				   GFP_KERNEL);
-	if (NULL == srcimp->imappers) {
+	if (!srcimp->imappers) {
 		err = -ENOMEM;
 		goto error1;
 	}
@@ -833,7 +833,7 @@
 
 	*rsrcimp_mgr = NULL;
 	srcimp_mgr = kzalloc(sizeof(*srcimp_mgr), GFP_KERNEL);
-	if (NULL == srcimp_mgr)
+	if (!srcimp_mgr)
 		return -ENOMEM;
 
 	err = rsc_mgr_init(&srcimp_mgr->mgr, SRCIMP, SRCIMP_RESOURCE_NUM, hw);
@@ -844,7 +844,7 @@
 	spin_lock_init(&srcimp_mgr->imap_lock);
 	INIT_LIST_HEAD(&srcimp_mgr->imappers);
 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
-	if (NULL == entry) {
+	if (!entry) {
 		err = -ENOMEM;
 		goto error2;
 	}