The 'dma-coherent' indicates that the hardware IP block can ensure
the coherency of the data transferred from/to the IP block. This
can avoid the software cache flush/invalid actions, and improve
the performance significantly.
The PCI IP block of ls1043a has this capability, so adding
this feature to improve the PCI performance.
Signed-off-by: Liu Gang <Gang.Liu@nxp.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Shawn Guo <shawnguo@kernel.org>