mesa: remove initialized field from uniform storage

The only place this was used was in a gallium debug function that
had to be manually enabled.

Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/compiler/glsl/ir_uniform.h

@@ -105,11 +105,6 @@ struct gl_uniform_storage {
     */
    unsigned array_elements;
 
-   /**
-    * Has this uniform ever been set?
-    */
-   bool initialized;
-
    struct gl_opaque_uniform_index opaque[MESA_SHADER_STAGES];
 
    /**