ARM: dts: exynos: add necessary clock controller inputs in Exynos5260

Exynos5260 bindings require to feed clock controllers with certain clock
inputs.  The IO clocks are expected to be provided by the board.  The
PHY clocks are usually followed by mux which can choose between the PHY
clock and main 24 MHz oscillator, so skip defining them and just use the
latter one.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20220102115356.75796-2-krzysztof.kozlowski@canonical.com