Since the switch from mmp_pdma to pxa_dma driver for pxa architectures,
the pxa_dma requires 2 arguments, namely the requestor line and the
requested priority.

Fix the only left device node which was still passing only one argument,
making the pxa3xx-nand driver misbehave in a device-tree configuration,
ie. failing all data transfers.

Fixes: c943646d ("ARM: dts: pxa: add dma engine node to pxa3xx-nand")
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>