dt-bindings: usb: samsung,exynos-usb2: add missing required reg

"reg" property is required on Samsung S5PV210/Exynos EHCI/OHCI
controllers.

Fixes: 4bf2283 ("dt-bindings: usb: samsung,exynos-usb2: convert to dtschema")
Reviewed-by: Alim Akhtar <[email protected]>
Acked-by: Rob Herring <[email protected]>
Signed-off-by: Krzysztof Kozlowski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: krzk

Documentation/devicetree/bindings/usb/samsung,exynos-usb2.yaml

@@ -62,6 +62,7 @@ required:
   - interrupts
   - phys
   - phy-names
+  - reg
 
 allOf:
   - if: