build(intel): add N5X as a new Intel platform

This commit adds a new Intel platform called N5X.
This preliminary patch only have Bl31 support.

Signed-off-by: Abdul Halim, Muhammad Hadi Asyrafi <muhammad.hadi.asyrafi.abdul.halim@intel.com>
Signed-off-by: Sieu Mun Tang <sieu.mun.tang@intel.com>
Change-Id: Ib31f9c4a5a0dabdce81c1d5b0d4776188add7195
5 files changed