dmaengine: Add ADM driver

Add the DMA engine driver for the QCOM Application Data Mover (ADM) DMA
controller found in the MSM8x60 and IPQ/APQ8064 platforms.

The ADM supports both memory to memory transactions and memory
to/from peripheral device transactions.  The controller also provides flow
control capabilities for transactions to/from peripheral devices.

The initial release of this driver supports slave transfers to/from peripherals
and also incorporates CRCI (client rate control interface) flow control.

Signed-off-by: Andy Gross <agross@codeaurora.org>

Conflicts:
	drivers/dma/Kconfig
	drivers/dma/Makefile