[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>

arch/ia64/ia32/binfmt_elf32.c

@@ -35,6 +35,9 @@ extern void ia64_elf32_init (struct pt_regs *regs);
 
 static void elf32_set_personality (void);
 
+static unsigned long __attribute ((unused))
+randomize_stack_top(unsigned long stack_top);
+
 #define setup_arg_pages(bprm,tos,exec)		ia32_setup_arg_pages(bprm,exec)
 #define elf_map				elf32_map