ARM: dts: exynos: remove unneeded DVS voltages from PMIC on Arndale

The S5M8767 PMIC does not require anymore a safe DVS voltage, if the DVS
GPIO is not enabled.  Although previously bindings required providing
this safe DVS voltage, but since commit 04f9f068

 ("regulator:
s5m8767: Modify parsing method of the voltage table of buck2/3/4") this
was ignored.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210928084949.27939-12-krzysztof.kozlowski@canonical.com