dt-bindings: mfd: Add bindings for AXP192 MFD device

The AXP192 PMIC is similar to the AXP202/AXP209, but with different
regulators, additional GPIOs, and a different IRQ register layout,
so it needs a new compatible string.
Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230511092609.76183-2-aidanmacdonald.0x0@gmail.comSigned-off-by: Lee Jones <lee@kernel.org>

Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml

@@ -90,6 +90,7 @@ properties:
     oneOf:
       - enum:
           - x-powers,axp152
+          - x-powers,axp192
           - x-powers,axp202
           - x-powers,axp209
           - x-powers,axp221