i2c: nomadik: factor platform data into state container

Move the former platform data struct nmk_i2c_controller into the
per-device state container struct i2c_nmk_client, and remove all
the platform data probe path hacks.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
[wsa: use 100kHz as default]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>