arm64: dts: mediatek: mt8183: Remove second opp-microvolt entries from gpu table

arm64: dts: mediatek: mt8183: Remove second opp-microvolt entries from gpu table

This was done to keep a strict relation between VSRAM and VGPU, but
it never worked: now we're doing it transparently with the new
mediatek-regulator-coupler driver.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20230301095523.428461-4-angelogioacchino.delregno@collabora.com
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>