Merge commit '3aff0c45' into for-next

These fixes are a dependency for the Zvkb patches, so I'm merging them
into for-next as well as fixes.

* commit '3aff0c45':
  RISC-V: Drop invalid test from CONFIG_AS_HAS_OPTION_ARCH
  kbuild: Add -Wa,--fatal-warnings to as-instr invocation