MIPS: ingenic: DTS: Fix invalid value in #dma-cells

The driver requires two cells and not just one.

Since these nodes are both disabled as no hardware currently use them,
this fix does not really requires a Fixes: tag.

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