Fix VS warning C4244: 'function': conversion from 'UINT32' to 'UINT16', possible loss of data. Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Liming Gao <liming.gao@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> [lersek@redhat.com: remove whitespace after casts] Reviewed-by: Laszlo Ersek <lersek@redhat.com>