85xx: Removed BEDBUG support from FSL 85xx boards

For some reason the MPC8544 enabled BEDBUG if PCI was enabled and that
got copied int the MPC8536, MPC8572 and P2020 DS boards.  The BEDBUG
support has never been made to work completely on e500/85xx so we
just disable it to save space and match the other FSL 85xx boards.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>