NaCl/GYP: remove references to prep_toolchain from libyuv. prep_toolchain is now a no-op.

BUG=none
TESTED=untested
R=tpsiaki@google.com

Review URL: https://webrtc-codereview.appspot.com/49769004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1378 16f28f9a-4ce2-e073-06de-1de4eb20be90

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1375
+Version: 1378
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1375
+#define LIBYUV_VERSION 1378
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

libyuv_nacl.gyp

@@ -21,9 +21,6 @@
         'build_newlib': 0,
         'build_pnacl_newlib': 1,
       },
-      'dependencies': [
-        '../../native_client/tools.gyp:prep_toolchain',
-      ],
       'include_dirs': [
         'include',
       ],