i2c: i801: fix unused-function warning

With CONFIG_PM, we get a harmless build warning:
drivers/i2c/busses/i2c-i801.c:1723:12: warning: ‘i801_resume’ defined but not used [-Wunused-function]
 static int i801_resume(struct device *dev)
            ^~~~~~~~~~~
drivers/i2c/busses/i2c-i801.c:1714:12: warning: ‘i801_suspend’ defined but not used [-Wunused-function]
 static int i801_suspend(struct device *dev)
            ^~~~~~~~~~~~

Follow design pattern from other drivers like i2c-brcmstb, i2c-mpc,
i2c-ocores, i2c-pnx, i2c-puv3, i2c-st, i2c-stu300 and i2c-mux-pca954x
and changing the ifdef CONFIG_PM to CONFIG_PM_SLEEP.

Fixes: a9c8088c ("i2c: i801: Don't restore config registers on runtime PM")
Signed-off-by: NAnders Roxell <anders.roxell@linaro.org>
Reviewed-by: NJean Delvare <jdelvare@suse.de>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-i801.c

@@ -1710,7 +1710,7 @@ static void i801_shutdown(struct pci_dev *dev)
 	pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg);
 }
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 static int i801_suspend(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);