IA64: fix swiotlb alloc_coherent for non DMA_64BIT_MASK devices, fix

Because dma_alloc_coherent() always required DMA zone even if DMA is
NOT necessary, FUJITA Tomonori posted a patch to fix it:

  http://marc.info/?l=linux-ia64&m=123314730923356&w=2

However, this fix needs one more patch to fix completely.
I tested and confirmed dma_alloc_coherent() returns
correct zone after applied following patch.

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>