linux-phytec-ti

powerpc/setup: cleanup the #ifdef CONFIG_TAU block

Use cpu_has_feature() instead of opencoding

Use IS_ENABLED() instead of #ifdef for CONFIG_TAU_AVERAGE

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>