Simplify ppc64 code setting toc_off.
Every function has a nominal toc pointer value, even if it isn't used,
so set toc_off for every code section to the value used in that object
file. The thinking here was that if a code section didn't use the toc
it could use the previous object file's toc pointer value. It can,
but doing so is only a gain if functions in that section are called
mostly from previous objects sharing the same toc. We lose if the
functions in question are called mostly from the current object or
following objects, and it's a good bet they will probably mostly be
called from the current object.
* elf64-ppc.c (ppc64_elf_next_input_section): Always set toc_off
to value for object file.