uboot-imx

moveconfig: Allow control of which implying configs are shown

Sometimes it is useful to display CONFIG_TARGET or CONFIG_CMD configs. Add
an option to control this.

Also we generally ignore implying configs which affect fewer than 5
boards. But sometimes it is useful to show those those, so add an option
that reduces the minimum to two.

ERRATUM configs are never useful for implying things, so ignore those.

Signed-off-by: Simon Glass <sjg@chromium.org>