dma-mapping: implement link range API

dma-mapping: implement link range API

Introduce new DMA APIs to perform DMA linkage of buffers
in layers higher than DMA.

In proposed API, the callers will perform the following steps:
dma_start_range(...)
if (dma_can_use_iova(...))
  dma_alloc_iova()
  for (page in range)
     dma_link_range(...)
else
  /* Fallback to legacy map pages */
  dma_map_page(...)
dma_end_range(...)

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>