Add Thread Local Storage Initial Exec support to LLD.
This patch adds the computation for the relocations as well as the relaxation from Initial Exec to Local Exec.
pld r9, x@got@tprel@pcrel add r9, r9, x@tls@pcrel
pld r9, x@got@tprel@pcrel lbzx r10, r9, x@tls@pcrel
Note that @tls@pcrel is actually encoded as R_PPC64_TLS with a one byte displacement.
For the above examples relaxing Intitial Exec to Local Exec:
paddi r9, r9, x@tprel nop
paddi r9, r13, x@tprel lbz r10, 0(r9)