dt-bindings: i2c: Drop unneeded quotes

[ Upstream commit fc114c75 ]

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

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Reviewed-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Stable-dep-of: d4e001ff ("dt-bindings: i2c: atmel,at91sam: correct path to i2c-controller schema")
Signed-off-by: Sasha Levin <sashal@kernel.org>