Since the O3 and Minor CPU models do not support RVV right now as the
implementation stalls the decode until vsetvl instructions are exectued,
this change calls `fatal` if RVV is not explicitly enabled.
It is possible to override this if you explicitly enable RVV in the
config file.
Change-Id: Ia801911141bb2fb2bedcff3e139bf41ba8936085
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>