Add the new CONFIG_* values to default-config/xtensa*-softmmu.mak.

Signed-off-by: Ákos Kovács <akoskovacs@gmx.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Message-Id: <20190202072456.6468-17-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>