mesa/sso: Fix typo of 'unsigned'.

Fix build error introduced with commit f4c13a890f.

  CC       pixeltransfer.lo
main/pipelineobj.c: In function '_mesa_delete_pipeline_object':
main/pipelineobj.c:59:4: error: unknown type name 'unsinged'
    unsinged i;
    ^

Signed-off-by: Vinson Lee <vlee@freedesktop.org>

src/mesa/main/pipelineobj.c

@@ -56,7 +56,7 @@ void
 _mesa_delete_pipeline_object(struct gl_context *ctx,
                              struct gl_pipeline_object *obj)
 {
-   unsinged i;
+   unsigned i;
 
    _mesa_reference_shader_program(ctx, &obj->_CurrentFragmentProgram, NULL);