Add some debug information for PXA DMA :
- descriptors queued
- channels state
- global state
--
Since V1: reverted to old register access (no more dma_readl() or dma_writel()).
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>