ALSA: ice1724: Fix build error without CONFIG_PM_SLEEP

Bah, forgot this again...

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/ice1712/ice1724.c b/sound/pci/ice1712/ice1724.c
index 4c52a31..ea99e56 100644
--- a/sound/pci/ice1712/ice1724.c
+++ b/sound/pci/ice1712/ice1724.c
@@ -2362,8 +2362,10 @@
 	}
 	printk(KERN_WARNING "ice1724: No matching model found for ID 0x%x\n",
 	       ice->eeprom.subvendor);
+#ifdef CONFIG_PM_SLEEP
 	/* assume AC97-only card which can suspend without additional code */
 	ice->pm_suspend_enabled = 1;
+#endif
 
  found:
 	ice->eeprom.size = snd_vt1724_read_i2c(ice, dev, 0x04);