ia64: fix build breakage in asm/thread_info.h

In commit 504f52b5
    mm: NUMA aware alloc_task_struct_node()

Eric Dumazet forgot a "\".  Add it.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>