Apply d799769188529abc6cbf035a10087a51f7832b6b to 5.17 and 5.15?

[Nathan Chancellor <nathan@kernel.org>]

Hi Greg, Sasha, and Michael,

Commit d79976918852 ("powerpc/64: Add UADDR64 relocation support") fixes
a boot failure with CONFIG_RELOCATABLE=y kernels linked with recent
versions of ld.lld [1]. Additionally, it resolves a separate boot
failure that Paul Menzel reported [2] with ld.lld 13.0.0. Is this a
reasonable backport for 5.17 and 5.15? It applies cleanly, resolves both
problems, and does not appear to cause any other issues in my testing
for both trees but I was curious what Michael's opinion was, as I am far
from a PowerPC expert.

This change does apply cleanly to 5.10 (I did not try earlier branches)
but there are other changes needed for ld.lld to link CONFIG_RELOCATABLE
kernels in that branch so to avoid any regressions, I think it is safe
to just focus on 5.15 and 5.17.

Paul, it would not hurt to confirm the results of my testing with your
setup, just to make sure I did not miss anything :)

[1]: https://github.com/ClangBuiltLinux/linux/issues/1581
[2]: https://lore.kernel.org/Yg2h2Q2vXFkkLGTh@dev-arch.archlinux-ax161/

Cheers,
Nathan