Added platform notes for Qt Multimedia on Android.
Added platform notes for Qt Multimedia on Android.

Task-number: QTBUG-35075

Change-Id: I3840d048788321bef4fe655bef685af5b075d9ac
Reviewed-by: Lars Knoll <a812617a4072dcbeb80684eca0f369f0083af109@digia.com>
Reviewed-by: Jerome Pasion <c10995d24f6b454503389e8d00d837aef038985d@digia.com>

kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc