selinux: sparse fix: make selinux_secmark_refcount static

Sparse fix: make selinux_secmark_refcount  static.
Signed-off-by: James Morris <jmorris@namei.org>

security/selinux/hooks.c

@@ -96,7 +96,7 @@ extern int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm);
 extern struct security_operations *security_ops;
 
 /* SECMARK reference count */
-atomic_t selinux_secmark_refcount = ATOMIC_INIT(0);
+static atomic_t selinux_secmark_refcount = ATOMIC_INIT(0);
 
 #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
 int selinux_enforcing;