ARM: dts: stm32: introduce stm32h7-pinctrl.dtsi to support stm32h750

This patch is intend to add support stm32h750 value line,
just add stm32h7-pinctrl.dtsi for extending, with following changes:

- rename stm32h743-pinctrl.dtsi to stm32h7-pinctrl.dtsi
- move 'pin-controller' from stm32h7-pinctrl.dtsi to stm32h743.dtsi
- update stm32h743i-{disco, eval}.dts to include stm32h7-pinctrl.dtsi

Signed-off-by: dillon min <dillon.minfei@gmail.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/arch/arm/dts/stm32h743i-disco.dts b/arch/arm/dts/stm32h743i-disco.dts
index 7927310..3a01ebd 100644
--- a/arch/arm/dts/stm32h743i-disco.dts
+++ b/arch/arm/dts/stm32h743i-disco.dts
@@ -6,7 +6,7 @@
 
 /dts-v1/;
 #include "stm32h743.dtsi"
-#include "stm32h743-pinctrl.dtsi"
+#include "stm32h7-pinctrl.dtsi"
 
 / {
 	model = "STMicroelectronics STM32H743i-Discovery board";