Self Restore: Integrated build with rest of the EKB build flow.

Self restore binary used to get built by a shell script standalone.
It used to get checked in to EKB. Hardware image build infrastructure
used to just pick that binary and insert it into the hardware image.
This commit augments the EKB build flow by incorporating a capability
to build self restore binary like any other executable generated
during EKB build. Syntax to build binary:
   ekb build p9_core_restore_routines

Key_Cronus_Test=PM_REGRESS

Change-Id: I992fda7ff0daa6494b1cf46fd15872263bb3e714
Original-Change-Id: I68b2587eab2798b7b8a2a188187767fa53aaf12f
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/55259
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Cronus HW CI <cronushw-ci+hostboot@us.ibm.com>
Reviewed-by: Douglas R. Gilbert <dgilbert@us.ibm.com>
Reviewed-by: Richard J. Knight <rjknight@us.ibm.com>
Reviewed-by: Gregory S. Still <stillgs@us.ibm.com>