drivers/i2c: stm32: Add pinctrl configuration at driver init

Convert driver to pcintrl configuration using pcintrl helper
macros.
Pinctrl init sequence has to be done before bus_mutex initialization.

Driver dts bindings are updated to reflect usage of pinctrl-x
properties

Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
4 files changed