ARM: tegra: Add header file for pinctrl constants

This new header file defines pincontrol constants for Tegra to
use from Tegra's DTS file for pincontrol properties option.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>