In order to support more of the i.MX6UL/ULL-based SoMs and boards by
Kontron Electronics GmbH, we restructure the devicetrees to share common
parts and add new devicetrees for the missing boards.

Currently there are the following SoM flavors:
  * N6310: SoM with i.MX6UL-2, 256MB RAM, 256MB SPI NAND
  * N6311: SoM with i.MX6UL-2, 512MB RAM, 512MB SPI NAND (new)
  * N6411: SoM with i.MX6ULL, 512MB RAM, 512MB SPI NAND (new)

Each of the SoMs also features 1MB SPI NOR and an Ethernet PHY. The carrier
board for the evalkit is the same for all SoMs.

This series also includes some small fixes for the shared parts of the
devicetrees.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>