This converts all Tegra boards over to use driver model for I2C. The driver
is adjusted to use driver model and the following obsolete CONFIGs are
removed:

   - CONFIG_SYS_I2C_INIT_BOARD
   - CONFIG_I2C_MULTI_BUS
   - CONFIG_SYS_MAX_I2C_BUS
   - CONFIG_SYS_I2C_SPEED
   - CONFIG_SYS_I2C

This has been tested on:
- trimslice (no I2C)
- beaver
- Jetson-TK1

It has not been tested on Tegra 114 as I don't have that board.

Acked-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Simon Glass <sjg@chromium.org>