[PowerPC][lld] Account for additional X-Forms -> D-Form/DS-Forms load/stores...

[PowerPC][lld] Account for additional X-Forms -> D-Form/DS-Forms load/stores when relaxing initial-exec to local-exec

D153645 added additional X-Form load/stores that can be generated for TLS accesses.
However, these added instructions have not been accounted for in lld. As a result,
lld does not know how to handle them and cannot relax initial-exec to local-exec
when the initial-exec sequence contains these additional load/stores.

This patch aims to resolve https://github.com/llvm/llvm-project/issues/64424.

Differential Revision: https://reviews.llvm.org/D158197