Add in a platform_family value to crossystem

This implements a platform_family value within the crossystem utility,
as the platform (particularly for ARM) is not easily accessable elsewhere at
runtime.

For the ARM side this contains a table which is used to determine the platform
family based on the /proc/device-tree/compatible entry. Similarly on x86 the
table is used to check against PCI entries. Additional entries can be made
as new platform families emerge.

BUG=chromium-os:24669
TEST=Manual, verified that crossystem runs properly and returns a valid
platform_family value on various platforms (mario, alex, z600, x220, etc).

Change-Id: Id0e973902d27ead471c1243bcc6c3292acc8479d
Reviewed-on: https://gerrit.chromium.org/gerrit/13520
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Commit-Ready: Olof Johansson <olofj@chromium.org>
Reviewed-by: Olof Johansson <olofj@chromium.org>
Tested-by: Olof Johansson <olofj@chromium.org>
3 files changed