Unreviewed build fix. MSVC (and other compilers) need a default: case in switch statement.

* platform/graphics/avfoundation/MediaPlayerPrivateAVFoundation.cpp:
(WebCore::notificationName):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142328 268f45cc-cd09-0410-ab3c-d52691b4dbfc