arm64: dts: stratix10: Add QSPI support for Stratix10

Add qspi_clock
   The qspi_clk frequency is updated by U-Boot before starting Linux.
Add QSPI interface node.
Add QSPI flash memory child node.
   Setup the QSPI memory in 2 partitions.

Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>