powerpc/optprobes: Compact code source a bit.

Now that lines can be up to 100 chars long, minimise the
amount of split lines to increase readability.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8ebbd977ea8cf8d706d82458f2a21acd44562a99.1621516826.git.christophe.leroy@csgroup.eu