The change "core: allow offset-attached managed dataspaces" addressed a
corner case of the use of nested region maps. Apparently, this change
negatively affects other scenarios (tool_chain_auto).
In order to confidently cover all the differnt situations, this patch
reworks the page-fault resolution code for improved clarity and safety,
by introducing dedicated result types, reducing the use of basic types,
choosing expressive names, and fostering constness.
It also introduces a number of 'print' hooks that greatly ease manual
instrumentation and streamlines the error messages printed by core.
Those messages no longer appear when a user-level page-fault handler
is reistered for the faulted-at region map. So the monitor component
produces less noise on the attempt to dump non-existing memory.
Issue #4917Fixes#4920
* Remove SPEC declarations from mk/spec
* Remove all board-specific REQUIRE declaratiions left
* Replace [have_spec <board>] run-script declarations with have_board where necessary
* Remove addition of BOARD variable to SPECS in toplevel Makefile
* Move board-specific directories in base-hw out of specs
