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/doc/manual/installation/installing-usb.section.md

@@ -0,0 +1,31 @@
+# Booting from a USB Drive {#sec-booting-from-usb}
+
+For systems without CD drive, the NixOS live CD can be booted from a USB
+stick. You can use the `dd` utility to write the image:
+`dd if=path-to-image of=/dev/sdX`. Be careful about specifying the correct
+drive; you can use the `lsblk` command to get a list of block devices.
+
+::: {.note}
+::: {.title}
+On macOS
+:::
+
+```ShellSession
+$ diskutil list
+[..]
+/dev/diskN (external, physical):
+   #:                       TYPE NAME                    SIZE       IDENTIFIER
+[..]
+$ diskutil unmountDisk diskN
+Unmount of all volumes on diskN was successful
+$ sudo dd if=nix.iso of=/dev/rdiskN bs=1M
+```
+
+Using the \'raw\' `rdiskN` device instead of `diskN` completes in
+minutes instead of hours. After `dd` completes, a GUI dialog \"The disk
+you inserted was not readable by this computer\" will pop up, which can
+be ignored.
+:::
+
+The `dd` utility will write the image verbatim to the drive, making it
+the recommended option for both UEFI and non-UEFI installations.