ARM: dts: exynos: add missing HDMI supplies on SMDK5250

Add required VDD supplies to HDMI block on SMDK5250.  Without them, the
HDMI driver won't probe.  Because of lack of schematics, use same
supplies as on Arndale 5250 board (voltage matches).

Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Link: https://lore.kernel.org/r/20220208171823.226211-2-krzysztof.kozlowski@canonical.com