LoongArch: ld:Report an error when seeing an unrecognized relocation

If we generate an object file using an assembler with the new
relocations added, and then linking those files with an older
linker, the link will still complete and the linked file will
be generated.
In this case we should report an error instead of continuing
the linking process.

(cherry picked from commit 5966e2eb3fed61ebe5c091a074b368b9238a68c1)