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/tools/networking/mpack/build-fix.patch

@@ -0,0 +1,29 @@
+diff -ubr mpack-1.6-orig/unixos.c mpack-1.6/unixos.c
+--- mpack-1.6-orig/unixos.c	2013-08-17 14:32:38.102772775 +0200
++++ mpack-1.6/unixos.c	2013-08-17 14:32:43.180792505 +0200
+@@ -38,10 +38,6 @@
+ #define MAXHOSTNAMELEN 64
+ #endif
+ 
+-extern int errno;
+-extern char *malloc();
+-extern char *getenv();
+-
+ int overwrite_files = 0;
+ int didchat;
+ 
+Only in mpack-1.6: unixos.o
+Only in mpack-1.6: unixunpk.o
+Only in mpack-1.6: uudecode.o
+diff -ubr mpack-1.6-orig/xmalloc.c mpack-1.6/xmalloc.c
+--- mpack-1.6-orig/xmalloc.c	2013-08-17 14:32:38.102772775 +0200
++++ mpack-1.6/xmalloc.c	2013-08-17 14:33:08.900892319 +0200
+@@ -24,7 +24,6 @@
+  */
+ #include <stdio.h>
+ #include <string.h>
+-extern char *malloc(), *realloc();
+ 
+ char *xmalloc (int size)
+ {
+Only in mpack-1.6: xmalloc.o