Document licenses

Change-Id: I827a8de356f42217a64191a467fa850e3eb6f4ef
Reviewed-by: Topi Reiniö <topi.reinio@qt.io>

src/multimedia/doc/src/qtmultimedia-index.qdoc

@@ -139,6 +139,15 @@
      \li Base class for video presentation.
     \endtable
 
+    \section1 Licenses and Attributions
+
+    The Qt Quick Multimedia module is available under commercial licenses from \l{The Qt Company}.
+    In addition, it is available under free software licenses. Since Qt 5.4,
+    these free software licenses are
+    \l{GNU Lesser General Public License, version 3}, or
+    the \l{GNU General Public License, version 2}.
+    See \l{Qt Licensing} for further details.
+
     \section1 Related Information
 
     \section2 Guides

src/multimediawidgets/doc/src/qtmultimediawidgets-index.qdoc

@@ -48,6 +48,15 @@ file:
 QT += multimediawidgets
 \endcode
 
+\section1 Licenses and Attributions
+
+The Qt Quick Multimedia Widgets module is available under commercial licenses from \l{The Qt Company}.
+In addition, it is available under free software licenses. Since Qt 5.4,
+these free software licenses are
+\l{GNU Lesser General Public License, version 3}, or
+the \l{GNU General Public License, version 2}.
+See \l{Qt Licensing} for further details.
+
 \section1 Related Information
 
 \section2 Reference