We want to be able to make full system images for this system too, just
as we now can for the MT7623 platforms.
The package directory (mt7623n) is now a bit misnamed as it's overly
specific, but the precise set of platforms which we support this way
is evolving and we'll fix it up when the dust settles and we know what
nomenclature makes most sense.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>