ARM: dts: mx5: Fix IPU port node placement

The "port" node was misplaced in the original patch, therefore making
the LCD dysfunctional on this board. Fix this by moving the "port" DT
node into the "display {}" node.

Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>