Implement X_EXT, instruction IDs, and stalls in case of data hazards for the CORE-V-XIF
Created by: michael-platzer
This PR continues implementation of the CORE-V-XIF eXtension interface by adding the X_EXT
parameter to enable/disable the XIF, instruction IDs, and stalls in case there is a data hazard for an XIF instruction in the EX stage.