ANDROID: cfi: Change synchronize_rcu to synchronize_rcu_expedited

Currenly,it uses synchronize_rcu() to wait old rcu reader to go away
in update_shadow.In embedded platform like ARM CA7X,
load_module blocks 40~50ms in update_shadow.
When there are more than one hundred kernel modules,
it blocks several seconds.

To accelerate load_module,change synchronize_rcu to
synchronize_rcu_expedited

Bug: 236922027
Signed-off-by: Haibo Li <haibo.li@mediatek.com>
Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Change-Id: Id966cdce44615b9994479608b91c3250ed8bd0d5