target: reshuffle headers

Create a new headers, drivers/target/target_core_internal.h that is supposed
to hold all target_core-internal prototypes.  Move all non-exported includes
from include/target to it, and merge the smaller prototype-only includes
inside drivers/target into it as well.  Mark functions that were found to
not be called outside their implementation file static.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index 6845228..47bc26b 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -38,6 +38,7 @@
 #include <target/target_core_fabric_ops.h>
 #include <target/target_core_configfs.h>
 
+#include "target_core_internal.h"
 #include "target_core_alua.h"
 #include "target_core_pr.h"