mfld-pmu: remove USB from hang device list of RTPM

mfld-pmu: remove USB from hang device list of RTPM

BZ: 24239

Remove USB from the hang device list of RTPM.

Change-Id: If25f1d1797d95adb2672aff27bba2ae4bc1850d7
Signed-off-by: Wu, Hao <hao.wu@intel.com>
Reviewed-on: http://android.intel.com:8080/39414
Reviewed-by: Zhuang, Jin Can <jin.can.zhuang@intel.com>
Reviewed-by: Singh, Youvedeep <youvedeep.singh@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: Monroy, German <german.monroy@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>