starfive visionfive2: let u-boot set device tree name

u-boot is able to automatically set the correct device tree name
on VisionFive 2 boards by reading their EEPROM since v2023.10.

This allows our image to work with either revision of the boards.

Reference: 16dbe3d9d4

starfive/visionfive/v2/README.md

@@ -56,12 +56,6 @@ nix build .#
 
 ## Additional configuration
 Additional configuration may be needed depending on your specific hardware configuration.
-### Board rev 1.2A
-If you have the 1.2A board revision add the following to your config:
-``` nix
-hardware.deviceTree.name =
-  lib.mkDefault "starfive/jh7110-starfive-visionfive-2-v1.2a.dtb";
-```
 
 ### 8GB memory
 If your board has 8GB of RAM add the following to your config:

starfive/visionfive/v2/default.nix

@@ -18,7 +18,4 @@
       generic-extlinux-compatible.enable = lib.mkDefault true;
     };
   };
-
-  hardware.deviceTree.name =
-    lib.mkDefault "starfive/jh7110-starfive-visionfive-2-v1.3b.dtb";
 }