IA64: Remove COMPAT_IA32 support

commit 32974ad4 upstream

This just changes Kconfig rather than touching all the other files the
original commit did.

Patch description from the original commit :

  |  [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>

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Willy Tarreau <w@1wt.eu>