ARM: dts: imx6qdl-sabresd: add egalax touch screen support on i2c2 bus

Add egalax touch screen support on i2c2 bus, it is connected
to LVDS0, while the existing one on i2c3 bus is connected to
LVDS1.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>