ia64: remove CONFIG_SWIOTLB ifdefs

CONFIG_SWIOTLB is now unconditionally selected on ia64, so remove the
ifdefs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/20190813072514.23299-28-hch@lst.de


Signed-off-by: Tony Luck <tony.luck@intel.com>