dt-bindings: mfd: tps6594: Allow gpio-line-names

Setting the signal names in the device tree was already possible, but
it will lead to a warning. Allow the gpio-line-names property to fix
that.

Signed-off-by: Michael Walle <mwalle@kernel.org>
Acked-by: "Rob Herring (Arm)" <robh@kernel.org>
Signed-off-by: Lee Jones <lee@kernel.org>

Author: mwalle

Documentation/devicetree/bindings/mfd/ti,tps6594.yaml

@@ -41,6 +41,7 @@ properties:
   system-power-controller: true
 
   gpio-controller: true
+  gpio-line-names: true
 
   '#gpio-cells':
     const: 2