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/compilers/swift/patches/0006-clang-purity.patch

@@ -0,0 +1,16 @@
+Apply the "purity" patch (updated for 5.4.2).
+
+--- a/lib/Driver/ToolChains/Gnu.cpp
++++ b/lib/Driver/ToolChains/Gnu.cpp
+@@ -488,11 +488,5 @@
+     if (Args.hasArg(options::OPT_rdynamic))
+       CmdArgs.push_back("-export-dynamic");
+-
+-    if (!Args.hasArg(options::OPT_shared) && !IsStaticPIE) {
+-      CmdArgs.push_back("-dynamic-linker");
+-      CmdArgs.push_back(Args.MakeArgString(Twine(D.DyldPrefix) +
+-                                           ToolChain.getDynamicLinker(Args)));
+-    }
+   }
+
+   CmdArgs.push_back("-o");