wire up armv4 tests

as a result of
https://lore.kernel.org/llvm/20230118-v4-v4t-lld-16-v1-1-e3d9a00ae47c@kernel.org/
https://github.com/ClangBuiltLinux/linux/issues/964

we should wire up an armv4 test in CI.  Not sure which config is the best target (if we could only choose one), maybe @arndb has advice?