dt-bindings: arm: apple: Add iMac (24-inch 2021) to Apple bindings

This introduces compatible strings for both 2021 Apple iMac M1 devices:

* apple,j456 - iMac (24-inch, 4x USB-C, M1, 2021)
* apple,j457 - iMac (24-inch, 2x USB-C, M1, 2021)

Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
Signed-off-by: Janne Grunau <j@jannau.net>
Tested-by: Hector Martin <marcan@marcan.st>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hector Martin <marcan@marcan.st>

Documentation/devicetree/bindings/arm/apple.yaml

@@ -12,12 +12,12 @@ maintainers:
 description: |
   ARM platforms using SoCs designed by Apple Inc., branded "Apple Silicon".
 
-  This currently includes devices based on the "M1" SoC, starting with the
-  three Mac models released in late 2020:
+  This currently includes devices based on the "M1" SoC:
 
   - Mac mini (M1, 2020)
   - MacBook Pro (13-inch, M1, 2020)
   - MacBook Air (M1, 2020)
+  - iMac (24-inch, M1, 2021)
 
   The compatible property should follow this format:
 
@@ -56,6 +56,8 @@ properties:
               - apple,j274 # Mac mini (M1, 2020)
               - apple,j293 # MacBook Pro (13-inch, M1, 2020)
               - apple,j313 # MacBook Air (M1, 2020)
+              - apple,j456 # iMac (24-inch, 4x USB-C, M1, 2021)
+              - apple,j457 # iMac (24-inch, 2x USB-C, M1, 2021)
           - const: apple,t8103
           - const: apple,arm-platform