libata-sff: introduce ata_sff_init/exit() and ata_sff_port_init()

In preparation of proper SFF/BMDMA separation, introduce
ata_sff_init/exit() and ata_sff_port_init().  These functions
currently don't do anything.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 132da80..d89502f 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -203,6 +203,16 @@
 /* libata-sff.c */
 #ifdef CONFIG_ATA_SFF
 extern void ata_pio_task(struct work_struct *work);
+extern void ata_sff_port_init(struct ata_port *ap);
+extern int ata_sff_init(void);
+extern void ata_sff_exit(void);
+#else /* CONFIG_ATA_SFF */
+static inline void ata_sff_port_init(struct ata_port *ap)
+{ }
+static inline int ata_sff_init(void)
+{ return 0; }
+static inline void ata_sff_exit(void)
+{ }
 #endif /* CONFIG_ATA_SFF */
 
 #endif /* __LIBATA_H__ */