ieee1394: conditionally export ieee1394_bus_type

Follow-up to patch "Consolidate driver registering":
Since I plan the lifetime of Linux 2.6.20 to be the deprecation phase
of CONFIG_IEEE1394_EXPORT_FULL_API, it seems fair to keep all previously
exported symbols available with this option until this phase is over.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Documentation/feature-removal-schedule.txt

@@ -52,7 +52,8 @@ Who:	Dan Dennedy <dan@dennedy.org>, Stefan Richter <stefanr@s5r6.in-berlin.de>
 
 What:	ieee1394 core's unused exports (CONFIG_IEEE1394_EXPORT_FULL_API)
 When:	January 2007
-Why:	There are no projects known to use these exported symbols.
+Why:	There are no projects known to use these exported symbols, except
+	dfg1394 (uses one symbol whose functionality is core-internal now).
 Who:	Stefan Richter <stefanr@s5r6.in-berlin.de>
 
 ---------------------------

drivers/ieee1394/ieee1394_core.c

@@ -1240,6 +1240,7 @@ EXPORT_SYMBOL(hpsb_node_write);
 EXPORT_SYMBOL(__hpsb_register_protocol);
 EXPORT_SYMBOL(hpsb_unregister_protocol);
 #ifdef CONFIG_IEEE1394_EXPORT_FULL_API
+EXPORT_SYMBOL(ieee1394_bus_type);
 EXPORT_SYMBOL(nodemgr_for_each_host);
 #endif