selftests: kvm: Adding config fragments

[ Upstream commit c096397c ]

selftests kvm test cases need pre-required kernel configs for the test
to get pass.

Signed-off-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>