cbfstool: show "preserved" flag in cbfstool layout output

The flag is useful for updaters to determine which areas to leave
alone, such as VPD (vital product data) regions that are set in
factory and might contain unique (MAC addresses) or hard to obtain
(calibration output) data.

It's also useful to see which regions are marked as such.

Change-Id: Ic0a229d474b32ac156cfabc917714ce9d339bac6
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33604
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>

util/cbfstool/cbfstool.c

@@ -1045,6 +1045,8 @@ static int cbfs_layout(void)
 			qualifier = "read-only, ";
 		else if (region_is_modern_cbfs((const char *)current->name))
 			qualifier = "CBFS, ";
+		else if (current->flags & FMAP_AREA_PRESERVE)
+			qualifier = "preserve, ";
 		printf(" (%ssize %u, offset %u)\n", qualifier, current->size,
 				current->offset);