The DMA API requires that 32-bit DMA masks are always supported, but on
arm LPAE configs they do not currently work when memory is present
above 4GB.  Wire up the swiotlb code like for all other architectures
to provide the bounce buffering in that case.

Fixes: 21e07dba ("scsi: reduce use of block bounce buffers").
Reported-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Vignesh Raghavendra <vigneshr@ti.com>