ARM: dts: imx23-olinuxino: Remove unneeded "default-on"

The initial state of the gpio led can be set directly in "gpios" node.

Hence, linux,default-trigger can be removed.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>