ARM: dts: at91: nattis 2: remove unnecessary include

sama5d3_lcd.dtsi is already included by sama5d31.dtsi, itself included by
at91-linea.dtsi.

Link: https://lore.kernel.org/r/20191229203503.336593-1-alexandre.belloni@bootlin.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>