ata: ahci_brcmstb: Fix warnings with CONFIG_PM_SLEEP=n

When CONFIG_PM_SLEEP is disabled, brcm_ahci_{suspend,resume} are not
used, which causes such a build warning to occur:

CC drivers/ata/ahci_brcmstb.o
drivers/ata/ahci_brcmstb.c:212:12: warning: 'brcm_ahci_suspend' defined
but not used [-Wunused-function]
static int brcm_ahci_suspend(struct device *dev)
^
drivers/ata/ahci_brcmstb.c:224:12: warning: 'brcm_ahci_resume' defined
but not used [-Wunused-function]
static int brcm_ahci_resume(struct device *dev)
^
LD drivers/ata/built-in.o

Fixes: 766a2d979632 ("ata: add Broadcom AHCI SATA3 driver for STB chips")
Signed-off-by: Florian Fainelli <[e-mail]>
Acked-by: Brian Norris <[e-mail]>
Signed-off-by: Tejun Heo <[e-mail]>

drivers/ata/ahci_brcmstb.c

···
 			   priv->top_ctrl + SATA_TOP_CTRL_BUS_CTRL);
 }
 
+#ifdef CONFIG_PM_SLEEP
 static int brcm_ahci_suspend(struct device *dev)
 {
 	struct ata_host *host = dev_get_drvdata(dev);
···
 	brcm_sata_phys_enable(priv);
 	return ahci_platform_resume(dev);
 }
+#endif
 
 static struct scsi_host_template ahci_platform_sht = {
 	AHCI_SHT(DRV_NAME),