dt-bindings: phy: cadence-torrent: update reference file of docs

In commit fd7abc3c ("phy: cadence-torrent: Use a common header
file for Cadence SERDES"), phy-cadence-torrent.h was renamed to
phy-cadence.h. Fix it of the Documentation.
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Link: https://lore.kernel.org/r/20210506114940.22215-1-wanjiabing@vivo.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/phy/phy-cadence-torrent.yaml

@@ -118,7 +118,7 @@ patternProperties:
         description:
           Specifies the Spread Spectrum Clocking mode used. It can be NO_SSC,
           EXTERNAL_SSC or INTERNAL_SSC.
-          Refer include/dt-bindings/phy/phy-cadence-torrent.h for the constants to be used.
+          Refer include/dt-bindings/phy/phy-cadence.h for the constants to be used.
         $ref: /schemas/types.yaml#/definitions/uint32
         enum: [0, 1, 2]
         default: 0