arm64: dts: lx2160aqds: Add FSPI node properties

lx2160a-qds has 2 micron "mt35xu512aba" flashes of size 64M each
connected on A0 and B1 i.e on CS0 and CS3. Since flashes are connected
on different buses, only one flash can be probed at a time.

Add fspi node properties aligned with LX2160A-RDB fspi properties.

Signed-off-by: Kuldeep Singh <kuldeep.singh@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>