target/xtensa: implement block prefetch option opcodes

Block prefetch option adds a bunch of non-privileged opcodes that may be
implemented as nops since QEMU doesn't model caches.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
1 file changed