Remove require of cl_icd_dispatch to avoid double typedef (KhronosGroup#1458)

* Remove require of cl_icd_dispatch to avoid double typedef

* Update xml/cl.xml

Co-authored-by: Ben Ashbaugh <ben.ashbaugh@intel.com>

---------

Co-authored-by: Ben Ashbaugh <ben.ashbaugh@intel.com>

Author: Kerilk

xml/cl.xml

@@ -5902,7 +5902,8 @@ server's OpenCL/api-docs repository.
                 <type name="CL/cl_icd.h"/>
             </require>
             <require>
-                <type name="cl_icd_dispatch"/>
+                <!-- Defined in cl_icd.h -->
+                <!-- <type name="cl_icd_dispatch"/> -->
                 <type name="cl_layer_info"/>
                 <type name="cl_layer_api_version"/>
             </require>