target: Add __exit annotation for module_exit functions

Inclues sbp_exit, fileio_module_exit, iblock_module_exit and
pscsi_module_exit.

Note: rd_module_exit() can not be annotated by __exit, becasue it is
called by target_core_init_configfs() which is annotated by __init.
Signed-off-by: NAsias He <asias@redhat.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

drivers/target/sbp/sbp_target.c

@@ -2598,7 +2598,7 @@ static int __init sbp_init(void)
 	return 0;
 };
 
-static void sbp_exit(void)
+static void __exit sbp_exit(void)
 {
 	sbp_deregister_configfs();
 };

drivers/target/target_core_file.c

@@ -631,7 +631,7 @@ static int __init fileio_module_init(void)
 	return transport_subsystem_register(&fileio_template);
 }
 
-static void fileio_module_exit(void)
+static void __exit fileio_module_exit(void)
 {
 	transport_subsystem_release(&fileio_template);
 }

drivers/target/target_core_iblock.c

@@ -821,7 +821,7 @@ static int __init iblock_module_init(void)
 	return transport_subsystem_register(&iblock_template);
 }
 
-static void iblock_module_exit(void)
+static void __exit iblock_module_exit(void)
 {
 	transport_subsystem_release(&iblock_template);
 }

drivers/target/target_core_pscsi.c

@@ -1178,7 +1178,7 @@ static int __init pscsi_module_init(void)
 	return transport_subsystem_register(&pscsi_template);
 }
 
-static void pscsi_module_exit(void)
+static void __exit pscsi_module_exit(void)
 {
 	transport_subsystem_release(&pscsi_template);
 }