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/ocaml-modules/mirage-xen/pkg-config.patch

@@ -0,0 +1,13 @@
+diff --git a/lib/bindings/mirage-xen.pc b/lib/bindings/mirage-xen.pc
+index a03a217..8499aa4 100644
+--- a/lib/bindings/mirage-xen.pc
++++ b/lib/bindings/mirage-xen.pc
+@@ -1,6 +1,6 @@
+-prefix=${pcfiledir}/../..
++prefix=@out@
+ exec_prefix=${prefix}
+-libdir=${exec_prefix}/lib
++libdir=@OCAMLFIND_DESTDIR@
+ 
+ Name: mirage-xen
+ Version: 6.0.0