ipq40xx: remove DK01 and DK04 boards

ipq40xx: remove DK01 and DK04 boards

DK01 and DK04 board support has been in a form of 2 patches that we have
been carrying for a long time.
Both of the patches contain weird changes, dont follow any DT syntax and I
honestly doubt they are even valid.
DK01 and DK04 also have not been converted to DSA even after a long time
and I doubt that anybody in the community even has these boards as they are
QCA reference boards that are not even obtainable anymore.

Since patches for these 2 boards have been just causing us pain when trying
to update the kernel to a new major release or even point releases lets
remove the support for these boards, and if there are users they can easily
be reinstated.

Signed-off-by: Robert Marko <robimarko@gmail.com>