ACPI: Remove CBMEM TOC from GNVS

This existed for ChromeOS but was no longer used with DYNAMIC_CBMEM.
See commit a0b4a8d.

Change-Id: Iae82498ab729df5682d89e66bb9de96457e91619
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/7465
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Tested-by: build bot (Jenkins)