target: use per-attribute show and store methods

This also allows to remove the target-specific old configfs macros, and
gets rid of the target_core_fabric_configfs.h header which only had one
function declaration left that could be moved to a better place.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org>
Acked-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/tcm_fc/tfc_io.c

@@ -44,7 +44,6 @@
 
 #include <target/target_core_base.h>
 #include <target/target_core_fabric.h>
-#include <target/configfs_macros.h>
 
 #include "tcm_fc.h"