ARM: tegra: call regulators_enable_boot_on on board init

Call regulators_enable_boot_on on board init to set all regulators
with boot-on property in device tree. If regulator is not used by
any device in the device tree but is essential for the device to
work a regression will occur.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>