drivers: dma: introduce Intel CAVS DMA

Introduce the Intel CAVS DMA. This is based out of the DesignWare
DMA IP but the register offset and bits have been changed in some
cases. However, the fundamental definition for the register field
has not been changed. Hence the registers begin with "DW_" to
indicate the Designware origin.

This driver currently supports the single block mode and linked list
multi-block mode. Scatter-Gather is not supported.

Change-Id: I33a8ed5141d9236167de50e14d3d407e95d6f553
Signed-off-by: Rajavardhan Gundi <rajavardhan.gundi@intel.com>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>