ich9: Simplify ich9_lpc_initfn

Currently, ich9_lpc_initfn simply serves as a caller to
ich9_lpc_add_properties. This simplifies the code a bit by eliminating
ich9_lpc_add_properties altogether and executing its logic in the parent
object initialiser function.

Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>