ARM: dts: nokia n900: drop unneeded/undocumented parts of the dts

Sakari mentioned that some parts of the dts are not needed and do
not have proper documentation, yet.

As the camera works without them, remove them for now.

Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Tony Lindgren <tony@atomide.com>