dt-bindings: clock: Drop unneeded quotes

Cleanup bindings dropping unneeded quotes. Once all these are fixed,
checking for this can be enabled in yamllint.

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230322173549.3972106-1-robh@kernel.org


Signed-off-by: Rob Herring <robh@kernel.org>