The 32bit build is creating this warning. Since we don't expect anyone
actually use this on 32bit, restrict ioatdma to be built only on x86_64.
This issue has long existed and only reason it's surfacing due to code
refactoring.

   drivers/dma/ioat/dma.c: In function 'ioat_timer_event':
>> drivers/dma/ioat/dma.c:870:39: warning: passing argument 2 of 'ioat_cleanup_preamble' from incompatible pointer type
     if (ioat_cleanup_preamble(ioat_chan, &phys_complete))
                                          ^
   drivers/dma/ioat/dma.c:577:13: note: expected 'u64 *' but argument is of type 'dma_addr_t *'
    static bool ioat_cleanup_preamble(struct ioatdma_chan *ioat_chan,
                ^
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>