Replace the code that sets up uncached PTEs with the generic vmap based
remapping code.  It also provides an atomic pool for allocations from
non-blocking context, which we not properly supported by the existing
nds32 code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Greentime Hu <greentime@andestech.com>
Reviewed-by: Greentime Hu <greentime@andestech.com>