TOMOYO: Do not call tomoyo_realpath_init unless registered.

tomoyo_realpath_init() is unconditionally called by security_initcall().
But nobody will use realpath related functions if TOMOYO is not registered.

So, let tomoyo_init() call tomoyo_realpath_init().

This patch saves 4KB of memory allocation if TOMOYO is not registered.

Signed-off-by: Kentaro Takeda <takedakn@nttdata.co.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toshiharu Harada <haradats@nttdata.co.jp>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/tomoyo/realpath.h b/security/tomoyo/realpath.h
index 0ea541f..7ec9fc9c 100644
--- a/security/tomoyo/realpath.h
+++ b/security/tomoyo/realpath.h
@@ -60,4 +60,7 @@
 /* Set memory quota. */
 int tomoyo_write_memory_quota(struct tomoyo_io_buffer *head);
 
+/* Initialize realpath related code. */
+void __init tomoyo_realpath_init(void);
+
 #endif /* !defined(_SECURITY_TOMOYO_REALPATH_H) */