ARM: dts: socfpga: add fpga region support on Arria10

Add the base FPGA region for DT overlay support in FPGA programming.

Signed-off-by: Alan Tull <atull@opensource.altera.com>
Signed-off-by: Matthew Gerlach <mgerlach@opensource.altera.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>