* some machines(MC-R700 etc) have pre-vrc4172 asic.
they don's work as vrc4172 specification, so skip some probe sequence.
- add platid related parameter.
- add VRC4172PWM_BROKEN_PROBE code.
* add MC-R700,700A parameters (tested on MC-R700).
* add contrast parameters.(but no one use yet).
* turn some message in probing to VPRINTF().
* enlarge VRC2_PWM_N_BRIGHTNESS.