ARM: dts: at91: sama5d27_som1: Add SPI NOR flash mapping

Add SoM1 flash mapping, identical with the other SPI NOR flash
mappings found on the other at91 boards.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Tested-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200403061222.1277147-2-tudor.ambarus@microchip.com


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