[SCSI] target: Minor sparse warning fixes and annotations

This patch addresses the majority of sparse warnings and adds
proper locking annotations.  It also fixes the dubious one-bit signed
bitfield, for which the signed one-bit types can be 0 or -1 which can
cause a problem if someone ever checks if (foo->lu_gp_assoc == 1).
The current code is fine because everyone just checks zero vs non-zero.
But Sparse complains about it so lets change it.  The warnings look like
this:

include/target/target_core_base.h:228:26: error: dubious one-bit signed bitfield

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Fubo Chen <fubo.chen@gmail.com>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/include/target/target_core_transport.h b/include/target/target_core_transport.h
index 2e8ec51..59aa464 100644
--- a/include/target/target_core_transport.h
+++ b/include/target/target_core_transport.h
@@ -109,6 +109,8 @@
 struct se_mem;
 struct se_subsystem_api;
 
+extern struct kmem_cache *se_mem_cache;
+
 extern int init_se_global(void);
 extern void release_se_global(void);
 extern void init_scsi_index_table(void);
@@ -190,6 +192,8 @@
 extern int transport_generic_do_tmr(struct se_cmd *);
 /* From target_core_alua.c */
 extern int core_alua_check_nonop_delay(struct se_cmd *);
+/* From target_core_cdb.c */
+extern int transport_emulate_control_cdb(struct se_task *);
 
 /*
  * Each se_transport_task_t can have N number of possible struct se_task's