is_buffer_dma_capable helper function is to see if a memory region is
DMA-capable or not. The arugments are the dma_mask (or
coherent_dma_mask) of a device and the address and size of a memory
region.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>