Catch Unknown Values for CONFIG_APPLY attribute

  - If an unknown value is encountered the default value
    will be used instead

Change-Id: I151574914d4e2a72fd4cdca0ca014dd45eab9ac8
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/73256
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: Corey V. Swenson <cswenson@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

src/usr/targeting/common/processMrw.pl

@@ -1869,6 +1869,13 @@ sub processXbus
             $config = $targetObj->getBusAttribute($target,0,"CONFIG_APPLY");
         }
 
+        # Validate a value was provided, if not use the default value
+        if ($config eq "")
+        {
+            print STDOUT "No value found for CONFIG_APPLY, default to using default value ($default_config)\n";
+            $config = $default_config;
+        }
+
         #If CONFIG_APPLY doesn't match the system configuration we are
         #running for, then mark the peers null.
         #For example, in wrap config, CONFIG_APPLY is expected to have "w"