BaseTools: Fix CLANGDWARF LoongArch64 ASLC build

When building a module containing .aslc files on the CLANGDWARF LoongArch64
platform, errors occur because the target and linker are set incorrectly.
Therefore, this patch:
- Add the missing target triplet to ASLCC_FLAGS so ACPI objects are
compiled for LoongArch64 rather than the host architecture.
- Add -fuse-ld=lld to ASLDLINK_FLAGS so linking does not fall back to the
GCC ld, which lacks elf64loongarch support.

Signed-off-by: Qihang Gao <gaoqihang@loongson.cn>
Signed-off-by: Chao Li <lichao@loongson.cn>