Use submodule way to access oniguruma. And upgrade oniguruma
version from v6.9.3 to v6.9.4_mark1.
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2073
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Shenglei Zhang