mesa/es: Remove redundant glGetVertexAttribPointer pname validation

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/mesa/main/APIspec.xml

@@ -2476,10 +2476,6 @@
 		<param name="pname" type="GLenum"/>
 		<vector name="pointer" type="GLvoid **" size="dynamic"/>
 	</proto>
-
-	<desc name="pname">
-		<value name="GL_VERTEX_ATTRIB_ARRAY_POINTER"/>
-	</desc>
 </template>
 
 <template name="GetBufferPointer" direction="get">