Document a configuration constraint
//
// Configurable parameters
+// - THREADS_PER_CORE must be 2 or greater.
// - Number of cache ways must be 1, 2, 4, or 8 (TLB_WAYS does not have
// this constraint). This is a limitation in the cache_lru module.
// - L1D_WAYS/L1I_WAYS must be greater than or equal to THREADS_PER_CORE,
