docs: dt: fix broken reference to phy-cadence-torrent.yaml

This file was removed, and another file was added instead of
it, on two separate commits.

Splitting a single logical change (doc conversion) on two
patches is a bad thing, as it makes harder to discover what
crap happened.

Anyway, this patch fixes the broken reference, making it
pointing to the new location of the file.

Fixes: 922003733d42 ("dt-bindings: phy: Remove Cadence MHDP PHY dt binding")
Fixes: c6d8eef38b7f ("dt-bindings: phy: Add Cadence MHDP PHY bindings in YAML format.")
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>
Link: https://lore.kernel.org/r/3f1cf6[e-mail]
Signed-off-by: Jonathan Corbet <[e-mail]>

Documentation/devicetree/bindings/phy/ti,phy-j721e-wiz.yaml

···
       bindings specified in
       Documentation/devicetree/bindings/phy/phy-cadence-sierra.txt
       Torrent SERDES should follow the bindings specified in
-      Documentation/devicetree/bindings/phy/phy-cadence-dp.txt
+      Documentation/devicetree/bindings/phy/phy-cadence-torrent.yaml
 
 required:
   - compatible