ARM: tegra: accept any SKU ID for most chips

For Tegra20, the SKU ID actually impacts how U-Boot programs the chip,
and hence we need to explicitly know about each and every SKU ID in order
to operate correctly.

However, for Tegra30/114, this isn't the case. Rather than forcing each
new user with a different SKU to manually add their SKU ID into the code,
simply accept any SKU ID.

If U-Boot ever starts e.g. programming maximal CPU clocks etc., we'll
need to undo this, or make the default case map to conservative defaults,
but for now it's likely the path to least support cost.

Reported-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>