ARM: dts: imx7d-pico: Add LCD support

Add support for the VXT VL050-8048NT-C01 panel connected through
the 24 bit parallel LCDIF interface.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Joris Offouga <offougajoris@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>