powerpc/configs/64s: Enable EMULATED_STATS

This is enabled in some of the other powerpc configs, and can be useful
for debugging, so enable it in ppc64[le]_defconfig.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230414132415.821564-19-mpe@ellerman.id.au