ref-manual: Added linuxloader.bbclass reference description.

(From yocto-docs rev: f33dbbd740ddd9dc88154373dc824e63d832ca0c)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/ref-classes.xml

@@ -1921,6 +1921,16 @@
     </para>
 </section>
 
+<section id='ref-classes-linuxloader'>
+    <title><filename>linuxloader.bbclass</filename></title>
+
+    <para>
+        Provides the function <filename>linuxloader()</filename>, which gives
+        the value of the dynamic loader/linker provided on the platform.
+        This value is used by a number of other classes.
+    </para>
+</section>
+
 <section id='ref-classes-logging'>
     <title><filename>logging.bbclass</filename></title>