ARM: dts: exynos: Silence i2c-gpio dtschema warning in Exynos5250 Arndale

The name of I2C controller over GPIO lines node ends with '-gpio' which
confuses dtschema:

  arch/arm/boot/dts/exynos5250-arndale.dt.yaml: soc: i2c-gpio:
    {'pinctrl-names': ['default'], ... 'phandle': [[65]]} is not of type 'array'
    From schema: lib/python3.6/site-packages/dtschema/schemas/gpio/gpio-consumer.yaml

Add a '-10' (there are already 0-9 I2C controllers on the SoC) suffix to
silence it.  This pattern on naming i2c-gpio is already present in many
other dts.  No functional change.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200901075417.22481-6-krzk@kernel.org