dt-bindings: iio: light: ltr501: Make proximity-near-level conditional

The proxmity-near-level attribute is only supported by ltr501 and ltr559
chips.

Signed-off-by: Esben Haabendal <esben@geanix.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

Documentation/devicetree/bindings/iio/light/liteon,ltr501.yaml

@@ -48,6 +48,18 @@ allOf:
       properties:
         interrupts: false
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - liteon,ltr301
+              - liteon,ltr303
+              - liteon,ltr329
+    then:
+      properties:
+        proximity-near-level: false
+
 examples:
   - |
     #include <dt-bindings/interrupt-controller/irq.h>