jetway/nf81-t56n-lf: Use hexdump() for dumping ACPI tables

Use hexdump() instead of a local implementation for dumping ACPI_TABLES.

Change-Id: I20354a4f9dff4105de5af696bb9da4a4f6cca788
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5466
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Tested-by: build bot (Jenkins)