integrity: special fs magic

Discussion on the mailing list questioned the use of these
magic values in userspace, concluding these values are already
exported to userspace via statfs and their correct/incorrect
usage is left up to the userspace application.

  - Move special fs magic number definitions to magic.h
  - Add magic.h include

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Reviewed-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/inode.c b/security/inode.c
index ca4958e..efea5a6 100644
--- a/security/inode.c
+++ b/security/inode.c
@@ -20,8 +20,7 @@
 #include <linux/init.h>
 #include <linux/namei.h>
 #include <linux/security.h>
-
-#define SECURITYFS_MAGIC	0x73636673
+#include <linux/magic.h>
 
 static struct vfsmount *mount;
 static int mount_count;