include/device: Split i2c.h into three

Split `i2c.h` into three pieces to ease reuse of the generic defi-
nitions. No code is changed.

* `i2c.h`        - keeps the generic definitions
* `i2c_simple.h` - holds the current, limited to one controller driver
                   per board, devicetree independent I2C interface
* `i2c_bus.h`    - will become the devicetree compatible interface for
                   native I2C (e.g. non-SMBus) controllers

Change-Id: I382d45c70f9314588663e1284f264f877469c74d
Signed-off-by: Nico Huber <>
Tested-by: build bot (Jenkins) <>
Reviewed-by: Aaron Durbin <>
76 files changed