Increase space for ACPI tables when using dynamic CBMEM

Unlike in old style CBMEM, dynamic CBMEM does not have a 
hand-calculated, hard-coded size, so allow up to 144K of
space for ACPI tables.

Change-Id: Id9dd7447c46d5fe7ed581be753d70e59add05320
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/6795
Tested-by: build bot (Jenkins)
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>