Davinci I2C initialization infrastructure; will be used by EVM init.

[ dbrownell@users.sourceforge.net: pass platform data into init code ]
Signed-off-by: Komal Shah <komal_shah802003@yahoo.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>