Use singleton instance of TargetService in mmio.C

There is a bug in the function that looks up the targeting service.
It is calling the constructor when it should just call the function
that looks up the singleton object.

Change-Id: I5ea91736e85c84927e3e0fe74352f61326e42940
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/71209
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Reviewed-by: Matt Derksen <mderkse1@us.ibm.com>
Reviewed-by: Corey V. Swenson <cswenson@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

src/usr/mmio/mmio.C

@@ -739,7 +739,7 @@ TARGETING::TargetHandle_t getParentProc(TARGETING::TargetHandle_t i_target)
     TARGETING::PredicateCTM     pred(TARGETING::CLASS_CHIP,
                                      TARGETING::TYPE_PROC);
 
-    TARGETING::TargetService().getAssociated(
+    TARGETING::targetService().getAssociated(
                                    list,
                                    i_target,
                                    TARGETING::TargetService::PARENT_BY_AFFINITY,