ARM: at91: dts: sama5d3: add missing pins of isi

The ISI has 12 data lines, add the missing two data lines.

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>