lib: add memrange infrastructure

The memrange infrastructure allows for keeping track of the
machine's physical address space. Each memory_range entry in
a memory_ranges structure can be tagged with an arbitrary value.
It supports merging and deleting ranges as well as filling in
holes in the address space with a particular tag.

The memrange infrastructure will serve as a shared implementation
for address tracking by the MTRR and coreboot mem table code.

Change-Id: Id5bea9d2a419114fca55c59af0fdca063551110e
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/2888
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/lib/Makefile.inc

@@ -86,6 +86,7 @@ ramstage-$(CONFIG_TRACE) += trace.c
 ramstage-$(CONFIG_COLLECT_TIMESTAMPS) += timestamp.c
 ramstage-$(CONFIG_COVERAGE) += libgcov.c
 ramstage-$(CONFIG_MAINBOARD_DO_NATIVE_VGA_INIT) += edid.c
+ramstage-y += memrange.c
 
 # The CBMEM implementations are chosen based on CONFIG_DYNAMIC_CBMEM.
 ifeq ($(CONFIG_DYNAMIC_CBMEM),y)