drop support for ReductionRatio which is not a power of two

By definition, the ReductionRatio is a number in range 1 to 65565.

However, all values which are not a power of two are optional.

For IO Controller implementation we always had the restriction that we do not support these optional values.

Having a look at new Profinet specification 2.4 it is obvious, that these optional values should not be used.

Removing support for these optional ReductionRatios will allow significant optimizations in scheduling code for handling PPM and CPM. Thus, the support of these non-power-of-two ReducationRatios shall be dropped.