dmaengine: dw: add support of iDMA 32-bit hardware

iDMA 32-bit is Intel designed DMA controller that behaves like Synopsys
Designware DMA. This patch adds a support of the new Intel hardware.

Due to iDMA 32-bit has no autoconfiguration the platform code must
provide a platform data to dw_dma_probe().

By default full FIFO (1024 bytes) is assigned to channel 0. Here we
slice FIFO on equal parts between channels for iDMA 32-bit case.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>