powerpc/configs/64s: Enable NO_HZ_FULL

At least Fedora & SUSE enable it.

VIRT_CPU_ACCOUNTING_GEN is selected so no longer needs to be in the
defconfig.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230414132415.821564-11-mpe@ellerman.id.au