ALSA: PCI: Replace CONFIG_PM with CONFIG_PM_SLEEP

Otherwise we may get compile warnings due to unused functions.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/ctxfi/ctatc.h b/sound/pci/ctxfi/ctatc.h
index 653e813..69b51f9 100644
--- a/sound/pci/ctxfi/ctatc.h
+++ b/sound/pci/ctxfi/ctatc.h
@@ -143,7 +143,7 @@
 
 	struct ct_timer *timer;
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 	int (*suspend)(struct ct_atc *atc);
 	int (*resume)(struct ct_atc *atc);
 #define NUM_PCMS (NUM_CTALSADEVS - 1)