remove dma operations in struct ia64_machine_vector

We don't need dma operation hooks in struct ia64_machine_vector
now. This also removes unused ia64_mv_dma_* typedefs.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>