Remove commit from U-Boot for now

It causes the rebuild of U-Boot and OpenSBI, as we are now bundling the
environment inside the U-Boot image.

lagarto-ox.nix

@@ -462,9 +462,6 @@
     uboot-env = let
       init = "${config.system.build.toplevel}/init";
       initrd = "${config.system.build.initialRamdisk}/initrd";
-      rev = if self ? rev then self.rev
-        else throw ("Refusing to build from a dirty Git tree!");
-
       # Create pmem of 3 GiB [0x140000000, 0x200000000)
       #fdt mknode / pmem@0x140000000
       #fdt set /pmem@0x140000000 compatible "pmem-region"
@@ -490,7 +487,6 @@
       #
     in prev.runCommand "uboot.txt" {} ''
       cat > $out <<EOF
-      git_commit=${rev}
       xtrace=yes
       bootargs=root=/dev/ram0 loglevel=7 rw earlycon=sbi console=hvc0 init=${init}
       ramdisk_size=$(stat --format %s $(readlink -f ${initrd}))