several issues in handling PNS_IF_SET_OEM_PARAMETERS_REQ with PrmType 6

There are several issues when using Set Oem ParameterType 6.

1. By definition it can not be used multiple times. If used multiple times it is expected that the error returned is meaningful. Currently the error 0xC0000002 (ERR_HIL_UNEXPECTED) is returned.
   Instead ERR_HIL_DATA_ALREADY_SET shall be used.
2. By definition it can not be used when firmware busstate is "on". Current implementation allows using the service even if busstate in "on".
   Service shall be rejected with ERR_HIL_OPERATION_NOT_POSSIBLE_IN_CURRENT_STATE in this case.
3. The DPM offset ocupied by this service shall be locked for other usage in protocol stack. Currently it is possible to plug a submodule at runtime which uses the same DPM offsets.
   Instead plugging a submodule shall be rejected if overlapping occurs.