ARM: tegra: remove copy-and-pasted i2c platform data in boards

Every board file includes the same platform data definition
for the i2c-tegra driver's bus speed.  Move the platform data
into devices.c, and remove it from all the board files.

Signed-off-by: Colin Cross <ccross@android.com>
Tested-by: Konstantin Sinyuk <kostyas@compulab.co.il>
Acked-by: Olof Johansson <olof@lixom.net>