MdePkg/Include: Add LOONGARCH related definitions EDK2 CI.

MdePkg/Include: Add LOONGARCH related definitions EDK2 CI.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4053

HTTP/PXE boot LOONGARCH64 related definitions for EDK2 CI.

For the LOONGARCH values, please seeing following URL section
"Processor Architecture Types":
https://www.iana.org/assignments/dhcpv6-parameters/dhcpv6-parameters.xhtml

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Signed-off-by: Chao Li <lichao@loongson.cn>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>