arm: tegra: export tegra_chip_uid

The crypto driver will need this api to use
it in the RNG calculations. In order to build
the crypto driver as a module, tegra_chip_uid
has to be exported.

Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Henning Heinold <heinold@inf.fu-berlin.de>
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>