uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

nixos/modules/profiles/qemu-guest.nix

@@ -0,0 +1,17 @@
+# Common configuration for virtual machines running under QEMU (using
+# virtio).
+
+{ config, lib, ... }:
+
+{
+  boot.initrd.availableKernelModules = [ "virtio_net" "virtio_pci" "virtio_mmio" "virtio_blk" "virtio_scsi" "9p" "9pnet_virtio" ];
+  boot.initrd.kernelModules = [ "virtio_balloon" "virtio_console" "virtio_rng" ];
+
+  boot.initrd.postDeviceCommands = lib.mkIf (!config.boot.initrd.systemd.enable)
+    ''
+      # Set the system time from the hardware clock to work around a
+      # bug in qemu-kvm > 1.5.2 (where the VM clock is initialised
+      # to the *boot time* of the host).
+      hwclock -s
+    '';
+}