uboot-imx

Enable DISTRO_DEFAULT on platforms that missed it before

A number of platforms had been using the distro default feature before
it was moved to Kconfig but did not enable the new Kconfig option when
it was enabled.  This caused a regression in terms of features and this
introduces breakage when more things move to Kconfig.

Signed-off-by: Tom Rini <trini@konsulko.com>