All radix guests go via the P9 path now, so there is no need to limit
nested HV to processors that support "mixed mode" MMU. Remove the
restriction.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-27-npiggin@gmail.com