spi: cdns: Add compatible for AMD Pensando Elba SoC

Document the cadence qspi controller compatible for AMD Pensando
Elba SoC boards.  The Elba qspi fifo size is 1024.

Signed-off-by: Brad Larson <blarson@amd.com
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org
Link: https://lore.kernel.org/r/20230515181606.65953-3-blarson@amd.com
Signed-off-by: Mark Brown <broonie@kernel.org

Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml

@@ -46,12 +46,28 @@ allOf:
           maxItems: 2
           items:
             enum: [ qspi, qspi-ocp ]
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: amd,pensando-elba-qspi
+    then:
+      properties:
+        cdns,fifo-depth:
+          enum: [ 128, 256, 1024 ]
+          default: 1024
+    else:
+      properties:
+        cdns,fifo-depth:
+          enum: [ 128, 256 ]
+          default: 128
 
 properties:
   compatible:
     oneOf:
       - items:
           - enum:
+              - amd,pensando-elba-qspi
               - ti,k2g-qspi
               - ti,am654-ospi
               - intel,lgm-qspi
@@ -76,8 +92,6 @@ properties:
     description:
       Size of the data FIFO in words.
     $ref: /schemas/types.yaml#/definitions/uint32
-    enum: [ 128, 256 ]
-    default: 128
 
   cdns,fifo-width:
     $ref: /schemas/types.yaml#/definitions/uint32