region: Turn region_end() into an inclusive region_last()

The current region_end() implementation is susceptible to overflow
if the region is at the end of the addressable space. A common case
with the memory-mapped flash of x86 directly below the 32-bit limit.

Note: This patch also changes console output to inclusive limits.
IMO, to the better.

Change-Id: Ic4bd6eced638745b7e845504da74542e4220554a
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79946
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

util/cbfstool/cse_serger.c

@@ -647,7 +647,7 @@ static size_t get_cse_region_end_offset(void)
 	size_t end_offset;
 
 	for (size_t i = 0; i < BP_TOTAL; i++) {
-		end_offset = region_end(&params.layout_regions[i]);
+		end_offset = region_last(&params.layout_regions[i]) + 1;
 		if (end_offset > offset)
 			offset = end_offset;
 	}