target/ppc: Restrict KVM-specific fields from ArchCPU

The 'kvm_sw_tlb' and 'tlb_dirty' fields introduced in commit
93dd5e852c ("kvm: ppc: booke206: use MMU API") are specific
to KVM and shouldn't be accessed when it is not available.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20230624192645.13680-1-philmd@linaro.org>
4 files changed