regulator: dt-bindings: pf8x00: fix nxp,phase-shift doc

nxp,phase-shift is an enum so use enum format to describe it.
Minimum and maximum values are also wrong.
Signed-off-by: NAdrien Grassein <adrien.grassein@gmail.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210114174714.122561-3-adrien.grassein@gmail.comSigned-off-by: NMark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/regulator/nxp,pf8x00-regulator.yaml

@@ -73,21 +73,11 @@ properties:
 
           nxp,phase-shift:
             $ref: "/schemas/types.yaml#/definitions/uint32"
-            minimum: 45
-            maximum: 0
+            default: 0
+            enum: [ 0, 45, 90, 135, 180, 225, 270, 315 ]
             description:
               BUCK regulators phase shift control in degrees.
 
-              Listed phase shift control values in degrees are,
-              45
-              90
-              135
-              180
-              225
-              270
-              315
-              0 (default)
-
         unevaluatedProperties: false
 
       "^vsnvs$":