[clang] [llvm] [PowerPC][ISelLowering] Support -mstack-protector-guard=tls (PR #110928)

[Nathan Chancellor via cfe-commits]

nathanchance wrote:

With [my series to fix `arch/powerpc`](https://git.kernel.org/pub/scm/linux/kernel/git/nathan/linux.git/log/?h=b4/powerpc-fix-stackprotector-test-clang) for this implementation applied to Linux, `CONFIG_HAVE_STACKPROTECTOR` is properly set and the Linux kernel dump test module (LKDTM)’s `REPORT_STACK_CANARY` test works correctly for both 32-bit and 64-bit. I think with a PowerPC specific review, we should be ready to land this.

https://github.com/llvm/llvm-project/pull/110928