arm64: dts: ti: iot2050: Add layout of OSPI flash

Describe the layout of the OSPI flash as the latest firmware uses it.
Specifically the location of the U-Boot envs is important for userspace
in order to access it.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Link: https://lore.kernel.org/r/d135b246bd302060175276d3653f2891077eb109.1674110442.git.jan.kiszka@siemens.com


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