MIPS: DTS: CI20: Misc. cleanups

- Use the standard "ecc-engine" property instead of the custom
"ingenic,bch-controller" to get a handle to the BCH controller.

- Respect cell sizes in the Ethernet controller node.

- Use proper macro for interrupt type instead of hardcoding magic
  values.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>