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>

pkgs/development/python-modules/pywal/convert.patch

@@ -0,0 +1,21 @@
+diff --git a/pywal/backends/wal.py b/pywal/backends/wal.py
+index a75fdc5..4339680 100644
+--- a/pywal/backends/wal.py
++++ b/pywal/backends/wal.py
+@@ -21,15 +21,7 @@ def imagemagick(color_count, img, magick_command):
+
+ def has_im():
+     """Check to see if the user has im installed."""
+-    if shutil.which("magick"):
+-        return ["magick", "convert"]
+-
+-    if shutil.which("convert"):
+-        return ["convert"]
+-
+-    logging.error("Imagemagick wasn't found on your system.")
+-    logging.error("Try another backend. (wal --backend)")
+-    sys.exit(1)
++    return ["@convert@"]
+
+
+ def gen_colors(img):