mainboard: Use decimal for `device domain 0x0 on`

Most boards use `device domain 0 on` with zero written in decimal.
For the sake of consistency, update the remaining boards to follow suit.

Change-Id: I6e2f0a19d57cfe6fc4e4ac4d14310133ad6b01d8
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/54358
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/src/mainboard/apple/macbookair4_2/devicetree.cb b/src/mainboard/apple/macbookair4_2/devicetree.cb
index b9c9c15..4ecc023 100644
--- a/src/mainboard/apple/macbookair4_2/devicetree.cb
+++ b/src/mainboard/apple/macbookair4_2/devicetree.cb
@@ -23,7 +23,7 @@
 		end
 	end
 
-	device domain 0x0 on
+	device domain 0 on
 		chip southbridge/intel/bd82x6x # Intel Series 6 Cougar Point PCH
 			register "c2_latency" = "0x0065"
 			register "docking_supported" = "0"