topology/switches: fix pep8
topology/switches: fix pep8

Signed-off-by: Yoshihiro Kaneko <fb9c50ad36156858cd51bb145369d6f181add714@gmail.com>
Signed-off-by: FUJITA Tomonori <93dac1fe9c4b2a3957982200319981492ad4976e@lab.ntt.co.jp>

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