powerpc/64s/hash: avoid the POWER5 < DD2.1 slb invalidate workaround on POWER8/9

I only have POWER8/9 to test, so just remove it for those.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2 files changed