dts: bindings: ethernet: Add required phy-connection-type

This commit updates the STM32 Ethernet binding to include
the `phy-connection-type` property as required.

Signed-off-by: IBEN EL HADJ MESSAOUD Marwa <[email protected]>

Author: marwaiehm-st

dts/bindings/ethernet/st,stm32-ethernet-common.yaml

@@ -18,3 +18,5 @@ properties:
     required: true
   pinctrl-names:
     required: true
+  phy-connection-type:
+    required: true