powerpc/85xx: p1022ds: disable the NOR flash node if video is enabled

The Freescale P1022 has a unique pin muxing "feature" where the DIU video
controller's video signals are muxed with 24 of the local bus address signals.
When the DIU is enabled, the bulk of the local bus is disabled, preventing
access to memory-mapped devices like NOR flash and the pixis FPGA.

Therefore, if the DIU is going to be enabled, then memory-mapped devices on
the localbus, like NOR flash, need to be disabled.

This also means that the localbus is not a 'simple-bus' any more, so remove
that string from the compatible node.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>