board: tegra30: switch to updated pre-dm i2c write

Configure PMIC voltages for early stages using updated
early i2c write.

Tested-by: Thierry Reding <treding@nvidia.com> # Beaver T30
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom <twarren@nvidia.com>