Add needed uart pinctrl configuration in pinmux node.
This is done thanks to <soc>-pinctrl.dtsi file matching
<soc>.dtsi files
Populate stm32 f3 based boards dts files with references
to uart pinctrl nodes
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
In order to simplify maintenance of dts files for
stm32f1 series, introduce a stm32f3.dtsi file which
represent the smallest common denominator of IPs in
the family.
Besides, stm32f334 includes stm32f303, as it is a
extension of this SoC.
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>