This commit mostly removes the globally visible NR_OF_CPUS define
from the global makefile specifiers defined in the base-hw repository.
Whereever necessary it adds platform specific makefiles to the base
repository when they were missing.
Ref #2190
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082