Revert "dt-bindings: iio: magnetometer: asahi-kasei,ak8975: Drop deprecated enums"

Reverted as Rob Herring is tracking undocumented compatibles and as per
discussion in the thread, we can not remove this deprecated compatibles from
the driver without potential/likely regressions.  So keep it around
as it's not that painful anyway.

This reverts commit 711fb79a.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/magnetometer/asahi-kasei,ak8975.yaml

@@ -18,6 +18,13 @@ properties:
           - asahi-kasei,ak09911
           - asahi-kasei,ak09912
           - asahi-kasei,ak09916
+      - enum:
+          - ak8975
+          - ak8963
+          - ak09911
+          - ak09912
+          - ak09916
+        deprecated: true
 
   reg:
     maxItems: 1