ARM: tegra: create common pre-dm i2c write

This implementation allows pwr i2c writing on early SPL
stages when DM is not yet setup.

Such writing is needed to configure main voltages of PMIC
on early SPL for bootloader to boot properly.

Tested-by: Andreas Westman Dorcsak <hedmoo@yahoo.com> # ASUS TF T30
Tested-by: Robert Eckelmann <longnoserob@gmail.com> # ASUS TF101 T20
Tested-by: Svyatoslav Ryhel <clamor95@gmail.com> # LG P895 T30
Tested-by: Thierry Reding <treding@nvidia.com> # T30 and T124
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Tom <twarren@nvidia.com>