Implement LoongArch CPU related functions in BaseCpuLib.
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>