dt-bindings: raspberrypi,bcm2835-firmware: Add 'power' and gpio-hog nodes

Add missing child nodes for the RaspberryPi firmware. The firmware
implements a power domain provider in a 'power' node. GPIO hog nodes are
also already in use.

Reviewed-by: Florian Fainelli <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Rob Herring (Arm) <[e-mail]>

Documentation/devicetree/bindings/arm/bcm/raspberrypi,bcm2835-firmware.yaml

···
       gpio-line-names:
         minItems: 8
 
+    patternProperties:
+      '-hog$':
+        required:
+          - gpio-hog
+
     required:
       - compatible
       - gpio-controller
···
     required:
       - compatible
       - "#reset-cells"
+
+  power:
+    $ref: /schemas/power/raspberrypi,bcm2835-power.yaml#
 
   pwm:
     type: object