security: Make capability_hooks static

Fix sparse warning:

security/commoncap.c:1347:27: warning:
 symbol 'capability_hooks' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: James Morris <jamorris@linux.microsoft.com>

security/commoncap.c

@@ -1344,7 +1344,7 @@ int cap_mmap_file(struct file *file, unsigned long reqprot,
 
 #ifdef CONFIG_SECURITY
 
-struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
+static struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(capable, cap_capable),
 	LSM_HOOK_INIT(settime, cap_settime),
 	LSM_HOOK_INIT(ptrace_access_check, cap_ptrace_access_check),