Additional FAPI migration to fapi2
Additional FAPI migration to fapi2

   Remove fapiSystemConfig.H - API is in target.H
   Add hwp_executor/plat_hwp_executor for FAPI_EXEC_HWP
   Migrate fapiAssert as fapi2::Assert

Change-Id: Ib7bc4f261f5223e45ca9f6555301b740c720f47c
Original-Change-Id: Ic25da30c05509501b03ecbb3ed68247bced2d707
Reviewed-on: http://gfw160.aus.stglabs.ibm.com:8080/gerrit/17652
Tested-by: Jenkins Server
Reviewed-by: Brian Silver <af0eed78d989d9597decc8b92fa6db01ef8b58e0@us.ibm.com>

open-power/hostboot,open-power/hostboot,open-power/hostboot,open-power/hostboot,open-power/hostboot