Replace WT_DCACHE define by CVA6ConfigCacheType localparam

[JeanRochCoulon]

Cache WT or WB was configured by a define.
#603 requests more description of it
#483 tells to not use define
#1122 reports a bug: WB is never used/verified

To solve these issues, WT_DCACHE define has been replaced by CVA6ConfigCacheType localparam

In GitHub Actions CI, cv32a6_imafc_sv32 has been added, this configuration implements WB.

[cfuguet]

Hi @JeanRochCoulon, I made an eye-review (no simulation), and it looks good.

However, I have one remark: currently you suppose a binary choice, either the WB or the WT cache. As you know, there is another cache subsystem that is showing the tip of the nose :).

Should not we have some kind of enumeration type that defines legal cache subsystem types:
enum {
WB = 0,
WT = 1,
// HPDcache = 2
} cache_type_t ;

This values can be used in the configuration package to select a given cache subsystem. We can then add new types to it if new cache subsystems are supported.

The question is now where to define this enumeration type. It cannot be in ariane_pkg because we will have a circular dependency between config packages and ariane_pkg. We could create an additional file: ariane_cache_pkg.sv. Constants from it can be imported from the config packages.

Just an idea...