Locking the root adapter for __i2c_transfer will deadlock if the
device sits behind a mux-locked I2C mux. Switch to the finer-grained
i2c_lock_bus with the I2C_LOCK_SEGMENT flag. If the device does not
sit behind a mux-locked mux, the two locking variants are equivalent.
Signed-off-by: Peter Rosin <peda@axentia.se>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>