Add some features to tegra_defconfig:
* Tegra+MAX98090 audio machine driver, as used on the Venice2 board.
* AMX3722 PMIC, as used on the Venice2 board.
* ChromeOS embedded controller, for the Venice2 keyboard.
Also, rebuild tegra_defconfig on a more recent kernel (3.13-rc1) to
minimize irrelevant diffs showing up when people edit the file.