ARM: dts: socfpga: Add Devkit A10-SR fields for Arria10

Add the Altera Arria10 System Resource node. This is a Multi-Function
device with GPIO expander support.

Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>