ARM: dts: Fix n900 dts file to work around 4.1 touchscreen regression on n900

Fix dts to match what the Linux kernel expects. This works around
touchscreen problems in 4.1 linux on Nokia n900.

Signed-off-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>