Pass AXI parameters uniquely through the CVA6 parameters

Created by: cfuguet

This pull requests replaces PR #1215.

These modifications remove redundant definitions of AXI parameters in the CVA6 core. AXI parameters are only passed through the top parameters and propagated.

Actual definition of AXI parameters must be performed at SoC level and pass during the CVA6 instantiation. This allows different instances of CVA6 in the same SoC to have different AXI parameters.