dma-contiguous: support per-numa CMA for all architectures

In the commit b7176c26

 ("dma-contiguous: provide the ability to
reserve per-numa CMA"), Barry adds DMA_PERNUMA_CMA for ARM64.

But this feature is architecture independent, so support per-numa CMA
for all architectures, and enable it by default if NUMA.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>