mtd: spi-nor-ids: Add is25lx512 chip

Added support for the ISSI OSPI flash part IS25LX512M.
Initial testing was performed on the Tenzing-se1 board using
SDR mode, covering basic erase, write, and readback operations.

Signed-off-by: Tejas Bhumkar <tejas.arvind.bhumkar@amd.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>