arm64: dts: apple: Add chassis-type property for Apple desktop devices

Apple's Mac mini and Studio are desktop devices. The SMBIOS has chassis
types which might be more accurate like "low profile desktop" or "mini
pc" but without clear definition what those are use plain "desktop" as
chassis-type in the root node.

Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
Link: https://patch.msgid.link/20260109-apple-dt-chassis-type-v1-2-c215503734c5@jannau.net
Signed-off-by: Sven Peter <sven@kernel.org>

Author: jannau

arch/arm64/boot/dts/apple/t600x-j375.dtsi

@@ -10,6 +10,8 @@
  */
 
 / {
+	chassis-type = "desktop";
+
 	aliases {
 		bluetooth0 = &bluetooth0;
 		ethernet0 = &ethernet0;

arch/arm64/boot/dts/apple/t8103-j274.dts

@@ -15,6 +15,7 @@
 / {
 	compatible = "apple,j274", "apple,t8103", "apple,arm-platform";
 	model = "Apple Mac mini (M1, 2020)";
+	chassis-type = "desktop";
 
 	aliases {
 		ethernet0 = &ethernet0;

arch/arm64/boot/dts/apple/t8112-j473.dts

@@ -15,6 +15,7 @@
 / {
 	compatible = "apple,j473", "apple,t8112", "apple,arm-platform";
 	model = "Apple Mac mini (M2, 2023)";
+	chassis-type = "desktop";
 
 	aliases {
 		ethernet0 = &ethernet0;