In order to be in line with other DT_INST macros in zephyr code base,
swap the arguments order in following macro definitions:
*ST_STM32_DT_PINCTRL
*ST_STM32_DT_INST_PINCTRL
Update the users accordingly.
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>