ARM: dts: imx7: remove DSI port endpoints

This fixes the display not working on colibri imx7, the driver fails to
load with the following error:

  mxsfb 30730000.lcdif: error -ENODEV: Cannot connect bridge

NXP i.MX7 LCDIF is connected to both the Parallel LCD Display and to a
MIPI DSI IP block, currently it's not possible to describe the
connection to both.

Remove the port endpoint from the SOC dtsi to prevent regressions, this
would need to be defined on the board DTS.

Reported-by: Hiago De Franco <hiagofranco@gmail.com>
Closes: https://lore.kernel.org/r/34yzygh3mbwpqr2re7nxmhyxy3s7qmqy4vhxvoyxnoguktriur@z66m7gvpqlia/
Fixes: edbbae7f

 ("ARM: dts: imx7: add MIPI-DSI support")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>