target: move external declarations to a headers

We should not declare extrnal .c symbols in C files to make sure they
match the actual prototype, and sparse correctly warns about this.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_internal.h

@@ -4,7 +4,13 @@
 /* target_core_alua.c */
 extern struct t10_alua_lu_gp *default_lu_gp;
 
+/* target_core_configfs.c */
+extern struct configfs_subsystem *target_core_subsystem[];
+
 /* target_core_device.c */
+extern struct mutex g_device_mutex;
+extern struct list_head g_device_list;
+
 struct se_dev_entry *core_get_se_deve_from_rtpi(struct se_node_acl *, u16);
 int	core_free_device_list_for_node(struct se_node_acl *,
 		struct se_portal_group *);

drivers/target/target_core_xcopy.c

@@ -34,20 +34,12 @@
 #include <target/target_core_fabric.h>
 #include <target/target_core_configfs.h>
 
+#include "target_core_internal.h"
 #include "target_core_pr.h"
 #include "target_core_ua.h"
 #include "target_core_xcopy.h"
 
 static struct workqueue_struct *xcopy_wq = NULL;
-/*
- * From target_core_device.c
- */
-extern struct mutex g_device_mutex;
-extern struct list_head g_device_list;
-/*
- * From target_core_configfs.c
- */
-extern struct configfs_subsystem *target_core_subsystem[];
 
 static int target_xcopy_gen_naa_ieee(struct se_device *dev, unsigned char *buf)
 {