Silicon/NXP: Add Chassis2 Package

A Chassis is a base framework used for building SoCs.
We can think of Chassis/Soc/Platform(a.k.a Board) in Object model terms.
Chassis is base. Soc is based on some Chassis.
Platform is based on some Soc.

SOCs that are designed around same chassis, reuse most of the components.

Therefore, add the package for Chassis2. LS1043A and LS1046A SOCs belong
to Chassis2.

Signed-off-by: Pankaj Bansal <pankaj.bansal@nxp.com>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>