dt-bindings: ufs: samsung,exynos-ufs: Add size constraints on "samsung,sysreg"

The 'phandle-array' type is a bit ambiguous. It can be either just an
array of phandles or an array of phandles plus args. "samsung,sysreg" is
the latter and needs to be constrained to a single entry with a phandle and
offset.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240124190733.1554314-1-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/ufs/samsung,exynos-ufs.yaml

@@ -55,9 +55,12 @@ properties:
 
   samsung,sysreg:
     $ref: /schemas/types.yaml#/definitions/phandle-array
-    description: Should be phandle/offset pair. The phandle to the syscon node
-                 which indicates the FSYSx sysreg interface and the offset of
-                 the control register for UFS io coherency setting.
+    items:
+      - items:
+          - description: phandle to FSYSx sysreg node
+          - description: offset of the control register for UFS io coherency setting
+    description:
+      Phandle and offset to the FSYSx sysreg for UFS io coherency setting.
 
   dma-coherent: true