drivers/pinmux: stm32: provide dt pinctrl to gpio driver interface

Provides tool set to be used by device drivers in order to be able
to configure device signals.
This does not involve the implementation of a dedicated pinctrl
driver. In this regard, this is equivalent to implementation used
for treatment of current pinmux.c files.

Since STM32F1 uses a different GPIO configuration scheme, its
support is exlcuded for now.

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