ARM: dts: s5pv210: correct MIPI CSIS clock name

commit 665b9459 upstream.

The Samsung S5P/Exynos MIPI CSIS bindings and Linux driver expect first
clock name to be "csis".  Otherwise the driver fails to probe.

Fixes: 94ad0f6d

 ("ARM: dts: Add Device tree for s5pv210 SoC")
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20230212185818.43503-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>