Add generic attribute accessor script and makefiles

  Added makefiles for generic and ocmb/explorer attrs
  Also add mssAccessorName tag to explorer attrs

Change-Id: Ie01f0462660a1ca20ae0c7fb29a290c88bfdfbbc
Original-Change-Id: I738c44e9bdf1999eb2746e79d4849683204ae567
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/69017
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Reviewed-by: Louis Stermole <stermole@us.ibm.com>
Tested-by: Hostboot CI <hostboot-ci+hostboot@us.ibm.com>
Reviewed-by: STEPHEN GLANCY <sglancy@us.ibm.com>
Reviewed-by: Christian R. Geddes <crgeddes@us.ibm.com>
Reviewed-by: Jennifer A. Stofer <stofer@us.ibm.com>
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/72338
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>
Tested-by: Daniel M. Crowell <dcrowell@us.ibm.com>