Add simple hexdump function

- prints hex and ascii
 - detects duplicate all zero lines

Change-Id: I557fed34f0f50ae256a019cf893004a0d6cbff7c
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/62655
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Tested-by: Stefan Reinauer <reinauer@chromium.org>
Commit-Queue: Stefan Reinauer <reinauer@chromium.org>
Reviewed-on: http://review.coreboot.org/4392
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/lib/Makefile.inc

@@ -113,6 +113,9 @@ romstage-$(CONFIG_HAVE_ACPI_RESUME) += cbmem.c
 endif # CONFIG_DYNAMIC_CBMEM
 ramstage-y += cbmem_info.c
 
+ramstage-y += hexdump.c
+romstage-y += hexdump.c
+
 ramstage-$(CONFIG_CONSOLE_NE2K) += ne2k.c
 
 ifneq ($(CONFIG_HAVE_ARCH_MEMSET),y)