[XIF] Making the XIF ID unique

[Joao-Pedro-Cabral]

As stated on the file cv32e40x_if_stage.sv on the commit 52c86ae0c95cadd005fae3f8c7425a72d0687d0c:
// TODO:XIF assert that the oustanding IDs are unique

And in my personal setup I got situations where the outstanding IDs are not unique.
This behavior can happens if in one cycle the ID offloads a instruction via XIF, then xif_offloading_id_i turns on.
However, it is possible for the ID stage updates its content to the next instruction, while the IF is stalled. In this situation, xif_offloading_id_i will be turned off before the IF stage ready to increment the xif_id register.

My solution is very simple, basically buffering the xif_offloading_id_i signal if the IF stage is not ready, and clearing it when IF is ready.

[Joao-Pedro-Cabral]

Sorry, can you help me with the ECA, I've never used this type of tool :/ ?
I created the account, linked my github account and accepted the ECA, but it's not working yet.