powerpc: Remove remaining parts of oprofile

Commit 9850b6c6

 ("arch: powerpc: Remove oprofile") removed
oprofile.

Remove all remaining parts of it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/298432fe1a14c0a415760011d72c3f0999efd5e2.1657204631.git.christophe.leroy@csgroup.eu