x86/unwind/orc: Fix !CONFIG_MODULES build warning

To fix follwowing warning due to ORC sort moved to build time:

  arch/x86/kernel/unwind_orc.c:210:12: warning: ‘orc_sort_cmp’ defined but not used [-Wunused-function]
  arch/x86/kernel/unwind_orc.c:190:13: warning: ‘orc_sort_swap’ defined but not used [-Wunused-function]
Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/c9c81536-2afc-c8aa-c5f8-c7618ecd4f54@linux.alibaba.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/unwind_orc.c

@@ -187,6 +187,8 @@ static struct orc_entry *orc_find(unsigned long ip)
 	return orc_ftrace_find(ip);
 }
 
+#ifdef CONFIG_MODULES
+
 static void orc_sort_swap(void *_a, void *_b, int size)
 {
 	struct orc_entry *orc_a, *orc_b;
@@ -229,7 +231,6 @@ static int orc_sort_cmp(const void *_a, const void *_b)
 	return orc_a->sp_reg == ORC_REG_UNDEFINED && !orc_a->end ? -1 : 1;
 }
 
-#ifdef CONFIG_MODULES
 void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size,
 			void *_orc, size_t orc_size)
 {