Roll FFmpeg DEPS to pick up MIPS config files.

petarj updated them here: https://gerrit.chromium.org/gerrit/70277

BUG=none
TEST=none
TBR=wolenetz
NOTRY=true

Review URL: https://codereview.chromium.org/294383002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@272655 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -218,7 +218,7 @@ deps = {
 
   "src/third_party/ffmpeg":
     Var("chromium_git") +
-    "/chromium/third_party/ffmpeg.git@7dd6164f6fe06017970107aba531e60fcc433282",
+    "/chromium/third_party/ffmpeg.git@90d4238be2656ee9d6b8f0cdfa5f96d40e6ed7ad",
 
   "src/third_party/libjingle/source/talk":
     (Var("googlecode_url") % "webrtc") + "/trunk/talk@" +