regulator: dt-bindings: Allow system-critical marking for fixed-regulator

In certain projects, the main system regulator, composed of simple
components including an under-voltage detector and capacitors, can be
aptly described as a fixed regulator in the device tree. To cater to
such use cases, this patch extends the fixed regulator binding to
support the 'system-critical-regulator' property. This property
signifies that the fixed-regulator is vital for system stability.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20231026144824.4065145-4-o.rempel@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/regulator/fixed-regulator.yaml

@@ -105,6 +105,8 @@ properties:
     description:
       Interrupt signaling a critical under-voltage event.
 
+  system-critical-regulator: true
+
 required:
   - compatible
   - regulator-name