Populate the IO pads and pins for Tegra264. Tegra264 has internal 1.8V
and 0.6V regulators that must be enabled when selecting the 1.8V mode
for the sdmmc1-hv IO pad. To support this a new 'ena_1v8' member is
added to the 'tegra_io_pad_vctrl' structure to populate the bits that
need to be set to enable these internal regulators. Although this is
enabling 1.8V (bit 1) and 0.6V (bit 2) regulators, it is simply called
'ena_1v8' because these are both enabled for 1.8V operation. Note that
these internal regulators are disabled when not using 1.8V mode.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Thierry Reding <treding@nvidia.com>