Improve performance to withstand netload class III normal test

In order to improve the performance in netload situations, the following changes should be made :

• RTA receive FIFO shall be increased from 8 to 32 elements. 
• The maximum number of processed RTC frames per RTC scheduler cycle shall be increased from the current maximum from 4 up to 16 frames per cycle.

This ensures that a network netload of 10%@ms can be withstood.