[PATCH] ia64: add ptr_to_compat()

Add ptr_to_compat() to ia64 - needed by the robust-futex code.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>