[PATCH] libata-hp: implement warmplug

Implement warmplug.  User-initiated unplug can be detected by
hostt->slave_destroy() and plug by transportt->user_scan().  This
patch only implements the two callbacks.  The next function will hook
them.

Signed-off-by: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 8df8ecc..c61cfc7 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -5942,6 +5942,7 @@
 EXPORT_SYMBOL_GPL(ata_scsi_ioctl);
 EXPORT_SYMBOL_GPL(ata_scsi_queuecmd);
 EXPORT_SYMBOL_GPL(ata_scsi_slave_config);
+EXPORT_SYMBOL_GPL(ata_scsi_slave_destroy);
 EXPORT_SYMBOL_GPL(ata_scsi_change_queue_depth);
 EXPORT_SYMBOL_GPL(ata_scsi_release);
 EXPORT_SYMBOL_GPL(ata_host_intr);