i2c-imx: add device tree probe support

It adds device tree probe support for i2c-imx driver.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Darius Augulis <augulis.darius@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>