MIPS: lantiq: dma: fix burst length for DEU

MIPS: lantiq: dma: fix burst length for DEU

[ Upstream commit 5ad74d39c51dd41b3c819f4f5396655f0629b4fd ]

The current definition of 2W burst length is invalid.
This patch fixes it. Current downstream DEU driver doesn't
use DMA. An incorrect burst length value doesn't cause any
errors. This patch also adds other burst length values.

Fixes: dfec1a827d2b ("MIPS: Lantiq: Add DMA support")
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>