ARM: dts: imx53-qsb: select open-drain mode for i2c1 pads

Both imx53-qsb and imx53-qsrb don't have external pull-up resistors
on the I2C1 SCL and SDA lines populated. Select open-drain mode and
enable the internal pull-up for both.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>