ALSA: ctxfi - Fix uninitialized error checks

Fix a few uninitialized error checks that were introduced recently
mistakenlly during the clean-up:
  sound/pci/ctxfi/ctamixer.c: In function ‘get_amixer_rsc’:
  sound/pci/ctxfi/ctamixer.c:261: warning: ‘err’ may be used uninitialized in this function
  sound/pci/ctxfi/ctamixer.c: In function ‘get_sum_rsc’:
  sound/pci/ctxfi/ctamixer.c:415: warning: ‘err’ may be used uninitialized in this function
  sound/pci/ctxfi/ctsrc.c: In function ‘get_srcimp_rsc’:
  sound/pci/ctxfi/ctsrc.c:742: warning: ‘err’ may be used uninitialized in this function

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/ctxfi/ctsrc.c b/sound/pci/ctxfi/ctsrc.c
index e1c145d..df43a5c 100644
--- a/sound/pci/ctxfi/ctsrc.c
+++ b/sound/pci/ctxfi/ctsrc.c
@@ -724,12 +724,11 @@
 
 	/* Allocate mem for SRCIMP resource */
 	srcimp = kzalloc(sizeof(*srcimp), GFP_KERNEL);
-	if (NULL == srcimp) {
-		err = -ENOMEM;
-		return err;
-	}
+	if (!srcimp)
+		return -ENOMEM;
 
 	/* Check whether there are sufficient SRCIMP resources. */
+	err = 0;
 	spin_lock_irqsave(&mgr->mgr_lock, flags);
 	for (i = 0; i < desc->msr; i++) {
 		err = mgr_get_resource(&mgr->mgr, 1, &idx);