libata: move ata_dev_disable() to libata-eh.c

ata_dev_disable() is about to be more tightly integrated into EH
logic.  Move it to libata-eh.c.

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 fe2839e..0a6f5be 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -79,7 +79,6 @@
 			   u64 block, u32 n_block, unsigned int tf_flags,
 			   unsigned int tag);
 extern u64 ata_tf_read_block(struct ata_taskfile *tf, struct ata_device *dev);
-extern void ata_dev_disable(struct ata_device *dev);
 extern void ata_pio_queue_task(struct ata_port *ap, void *data,
 			       unsigned long delay);
 extern void ata_port_flush_task(struct ata_port *ap);
@@ -160,6 +159,7 @@
 extern void ata_port_wait_eh(struct ata_port *ap);
 extern void ata_eh_fastdrain_timerfn(unsigned long arg);
 extern void ata_qc_schedule_eh(struct ata_queued_cmd *qc);
+extern void ata_dev_disable(struct ata_device *dev);
 extern void ata_eh_detach_dev(struct ata_device *dev);
 extern void ata_eh_about_to_do(struct ata_link *link, struct ata_device *dev,
 			       unsigned int action);