Most device headers contain SoC specific part and common Tegra post part.
Add a generic header which can be used by any Tegra device of one of the
supported SoC generations (T20, T30, T114, T124 or T210) without need in
device specific configuration.

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

Convert CFG_TEGRA_BOARD_STRING into Kconfig option and move it into device
board Kconfig.

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

Link CFG_SYS_NS16550_COM1 value to chosen CONFIG_TEGRA_ENABLE_UART Tegra
wide. Remove all CFG_SYS_NS16550_COM1 from device headers.

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

Convert boards to use text based env. This is the first stage of
conversion, common inclusions should be converted next.

Acked-by: Francesco Dolcini <francesco.dolcini@toradex.com> # Toradex Apalis TK1
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>

Use recently added ability to assign commands to buttons via env.

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

Nexus 7 is a mini tablet computer co-developed by Google and Asus
that runs the Android operating system. The Nexus 7 features a 7"
display, an Nvidia Tegra 3 quad-core chip, 1 GB of RAM and 8/16 GB
of internal storage.

This patch brings support for all 3 known ASUS/Google devices:
- Nexus 7 (2012) E1565
- Nexus 7 (2012) PM269
- Nexus 7 (2012) 3G - tilapia

Tested-by: Andreas Westman Dorcsak <hedmoo@yahoo.com> # ASUS Grouper E1565
Tested-by: Svyatoslav Ryhel <clamor95@gmail.com> # ASUS Grouper E1565
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>