base: Disable CPU caches via Exec.CacheControl().
base: Disable CPU caches via Exec.CacheControl().

This also flushes the caches, unlike the method of directly bashing
zero into CACR, and thus avoids losing memory writes in dirty cache
lines that never written back to main memory. This was observed on
a 68040 accelerator (A2000 Fusion 40).

keirf/Amiga-Stuff,keirf/Amiga-Stuff