arm64: dts: enable qspi-nor flash for Agilex NAND booting mode

In order to support FPGA RSU(Remote System Update) feature, it
also needs to enable qspi-nor flash even if Agilex platform boots
from NAND flash. Because the FPGA image is stored in nor flash.

Signed-off-by: Meng Li <Meng.Li@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>