RequestMap is used but not Initialized. RequestMap is called by UhciMapUserRequest, in which RequestMap(Map) is called by IoMmuMap, and is finally called by IoMmu->Map. We can not assume RequestMap is given an initial value at any step. Cc: Hao A Wu <hao.a.wu@intel.com> Cc: Ray Ni <ray.ni@intel.com> Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com> Reviewed-by: Hao A Wu <hao.a.wu@intel.com>