RISC-V Fixes for 6.8-rc7

* A fix for detecting ".option arch" support on not-yet-released LLVM
  builds.
* A fix for a missing TLB flush when modifying non-leaf PTEs.
* A handufl of fixes for T-Head custom extensions.
* A fix for systems with the legacy PMU, that manifests as a crash on
  kernels built without SBI PMU support.
* A fix for systems that clear *envcfg on suspend, which manifests as
  cbo.zero trapping after resume.
* A pair of fixes for Svnapot systems, including removing Svnapot
  support for huge vmalloc/vmap regions.
-----BEGIN PGP SIGNATURE-----
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=FpVN
-----END PGP SIGNATURE-----