ia64: annotate switch fallthroughs in ia64_handle_unaligned

Replace the "no break" comments with something that the compiler
recognizes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/20190812065524.19959-3-hch@lst.de


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