dt-bindings: fsi: Add P10 OCC device documentation

Add the P10 compatible string.

Signed-off-by: Eddie James <[e-mail]>
Reviewed-by: Joel Stanley <[e-mail]>
Signed-off-by: Joel Stanley <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Guenter Roeck <[e-mail]>

Documentation/devicetree/bindings/fsi/ibm,p9-occ.txt

···
-Device-tree bindings for FSI-attached POWER9 On-Chip Controller (OCC)
----------------------------------------------------------------------
+Device-tree bindings for FSI-attached POWER9/POWER10 On-Chip Controller (OCC)
+-----------------------------------------------------------------------------
 
-This is the binding for the P9 On-Chip Controller accessed over FSI from a
-service processor. See fsi.txt for details on bindings for FSI slave and CFAM
+This is the binding for the P9 or P10 On-Chip Controller accessed over FSI from
+a service processor. See fsi.txt for details on bindings for FSI slave and CFAM
 nodes. The OCC is not an FSI slave device itself, rather it is accessed
-through the SBE fifo.
+through the SBE FIFO.
 
 Required properties:
- - compatible = "ibm,p9-occ"
+ - compatible = "ibm,p9-occ" or "ibm,p10-occ"
 
 Examples: