usb:otg: wait for system resume before stopping host

usb:otg: wait for system resume before stopping host

BZ: 38545

add a PM notifier to know whether system is resumed.
EHCI driver should not be removed until system is resumed.

Change-Id: I012d1130215f08bd4230af8adf4068d8cb588c0b
Signed-off-by: jzhuan5 <jin.can.zhuang@intel.com>
Reviewed-on: http://android.intel.com:8080/52758
Reviewed-by: Wu, Hao <hao.wu@intel.com>
Reviewed-by: Tang, Jianqiang <jianqiang.tang@intel.com>
Reviewed-by: Tang, Richard <richard.tang@intel.com>
Reviewed-by: Meng, Zhe <zhe.meng@intel.com>
Tested-by: Meng, Zhe <zhe.meng@intel.com>
Reviewed-by: Gao, Yunpeng <yunpeng.gao@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>