arm64: dts: ti: k3-j721e-sk: Describe OSPI flash partition info

Describe OSPI flash partition information through device tree, this
helps to remove passing partition information through the mtdparts
commandline parameter which requires maintaining the partition
information in a string format. J721E SK has a S28 64 MiB OSPI flash
with sector size of 256 KiB thus the size of the smallest partition is
chosen as 256 KiB, the partition names and offsets are chosen according
to the corresponding name and offsets in bootloader.

Signed-off-by: Vaishnav Achath <vaishnav.a@ti.com>
Link: https://lore.kernel.org/r/20230513141712.27346-3-vaishnav.a@ti.com


Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>