MLK-20935-2 doc: imx: ahab: Include ahab_close command

Since commit 771b824728ca ("MLK-20919 imx8: ahab: Add command to
close the chip") the U-Boot is able to move the lifecycle from
NXP closed to OEM closed.

Update AHAB guides to use U-Boot ahab_close command instead of SCFW CLI.

As the procedure is now independent of SCFW terminal we can remove
this condition from documentation.

Signed-off-by: Breno Lima <breno.lima@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
(cherry picked from commit 6f93d877e1454024f666a4810d24148cf595429e)
2 files changed