arm: topology: Add support for topology DT bindings

Add support for parsing the explicit topology bindings to discover the
topology of the system.

Change-Id: I7f8a62d243fe1452408ab696ea2714aaa5b929eb
Signed-off-by: Venkatesh Yadav Abbarapu <vabbar@codeaurora.org>
[jshriram: using socket_id instead of cluster_id]
Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org>