Fix the EGLFS link in the QPA Plugins list

The EGLFS link pointed to a page under VxWorks documentation when
it should point to the embedded Linux documentation.

Task-number: QTBUG-72530
Change-Id: Id8dc789760194db92162b6632ad1a8eae4b05994
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

doc/src/platforms/emb-linux.qdoc

@@ -108,6 +108,7 @@
 
   \section1 Platform Plugins for Embedded Linux Devices
 
+  \target embedded eglfs
   \section2 EGLFS
 
   \l {http://www.khronos.org/egl}{EGL} is an interface between OpenGL and the

doc/src/platforms/qpa.qdoc

@@ -132,7 +132,7 @@ The following table summarizes the platform plugins available for QPA:
 \row
     \li \c qeglfs
     \li QEglFSIntegrationPlugin
-    \li \l EGLFS support for embedded Linux devices.
+    \li \l{embedded eglfs}{EGLFS} support for embedded Linux devices.
 \row
     \li \c qhaiku
     \li QHaikuIntegration