bindings: i2c: ti,mspm0g3xxx-i2c.yaml fix docs

explicitly note in the description that the expected phandle object
should be counter device type.

Signed-off-by: Dimitris Karnikis <[email protected]>

Author: dkarnikis

dts/bindings/i2c/ti,mspm0g3xxx-i2c.yaml

@@ -28,6 +28,7 @@ properties:
   watchdog-timer:
     type: phandle
     description: |
+      The type of the phandle object should be a counter device.
       When the system is crashing, the I2C lines (SDA/SCL) are not being
       reset and might stay LOW. To address this issue, we need to ensure that
       none of the user i2c driver callbacks (that are doing reads or writes)