nios2: Add Max10 device tree

Max10 is a FPGA device. This patch adds Nios2 support for Max10.
This device tree is based on Max10 hardware reference design.

Signed-off-by: Chee Nouk Phoon <cnphoon@altera.com>
Signed-off-by: Ley Foon Tan <lftan@altera.com>