KVM: selftests: Explicitly state indicies for vm_guest_mode_params array

Explicitly state the indices when populating vm_guest_mode_params to
make it marginally easier to visualize what's going on.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
[Added indices for new guest modes.]
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20211111000310.1435032-2-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>