[IA64] Remove COMPAT_IA32 support

This has been broken since May 2008 when Al Viro killed altroot support.
Since nobody has complained, it would appear that there are no users of
this code (A plausible theory since the main OSVs that support ia64 prefer
to use the IA32-EL software emulation).

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