powerpc: Enable LLDB on all powerpc architectures

[pkubaj]

Summary

While LLDB on powerpc and powerpcspe builds as-is, on powerpc64 and
powerpc64le it requires adding a couple of additional source files
to build.

Test Plan

make universe
try running lldb on target systems

[pkubaj]

Remove unrelated change.

[imp]

One nit that's more an out loud question than a required change.

share/mk/src.opts.mk

285

so only armv and riscv are broken? Maybe it's time to reverse the sense of this conditional?

[emaste]

share/mk/src.opts.mk

285

I suspect that 32-bit arm is fine, so it could probably be just != riscv. In any case though I think we can do it as a separate change.

[dim]

Fine with me.