configs: colibri-imx7: Enable bootd command

Enable boot/bootd command in toradex colibri-imx7 defconfig,
it's just convenient to have it in and every other toradex board
already includes it.

Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>