IntelSiliconPkg/VTd: Print Flags field in DeviceScopeEntry

Flags field is defined in Device Scope Structure since VT-d spec 4.0.
Print Device Scope Structure Flags field when dump DMAR table.

Change-Id: I37365ea4c1e6cfa0a1842a5830761367777b7d2c
Signed-off-by: Sheng Wei <w.sheng@intel.com>
Reviewed-by: Jenny Huang <jenny.huang@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rangasai V Chaganty <rangasai.v.chaganty@intel.com>
Cc: Jenny Huang <jenny.huang@intel.com>