Option CMD_SETEXPR is already default in U-boot [1], since this was
disabled since initial version for this board, there is send this
patch to U-boot mailing list to enable it.
It is required to use in OpenWrt bootscript for these boards [2].
[1] e95afa5675/cmd/Kconfig (L1504)
[2] 852126680e/target/linux/mvebu/image/clearfog.bootscript (L7)
Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>
