m68k: kernel: Add missing asmlinkage to do_notify_resume()

do_notify_resume() is called from assembly code, so it should be marked
asmlinkage for documentation purposes.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/e24d63ec4332316e859125caa8d07c0589603cfd.1694613528.git.geert@linux-m68k.org

arch/m68k/kernel/signal.c

@@ -1109,7 +1109,7 @@ static void do_signal(struct pt_regs *regs)
 	restore_saved_sigmask();
 }
 
-void do_notify_resume(struct pt_regs *regs)
+asmlinkage void do_notify_resume(struct pt_regs *regs)
 {
 	if (test_thread_flag(TIF_NOTIFY_SIGNAL) ||
 	    test_thread_flag(TIF_SIGPENDING))