DMA: Freescale: update driver to support 8-channel DMA engine

This patch adds support to 8-channel DMA engine, thus the driver works for both
the new 8-channel and the legacy 4-channel DMA engines.

Signed-off-by: Hongbo Zhang <hongbo.zhang@freescale.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --cc drivers/dma/Kconfig
Simple merge

diff --cc drivers/dma/fsldma.c
Simple merge

diff --cc drivers/dma/fsldma.h
Simple merge