[IA64] eliminate compile time warnings

This is a trivial patch to remove following compile time warning:

arch/ia64/ia32/../../../fs/binfmt_elf.c:508: warning: 'randomize_stack_top' defined but not used

Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>