arm: tegra: configs: Add GPIO regulator support

Enable CONFIG_GPIO_REGULATOR for Tegra3 platforms.

Bug 982788

Change-Id: I17587447013fdde6dc58b4fbf23f0ca37faa3dc5
Signed-off-by: Pavan Kunapuli <pkunapuli@nvidia.com>
Reviewed-on: http://git-master/r/101968
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>