signalfd: fix undefined reference to `compat_sys_signalfd4' when !CONFIG_SIGNALFD

fix:

arch/x86/ia32/built-in.o: In function `ia32_sys_call_table':
(.rodata+0xa38): undefined reference to `compat_sys_signalfd4'

on !CONFIG_SIGNALFD.

Signed-off-by: Ingo Molnar <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

kernel/sys_ni.c

···
 cond_syscall(sys_signalfd);
 cond_syscall(sys_signalfd4);
 cond_syscall(compat_sys_signalfd);
+cond_syscall(compat_sys_signalfd4);
 cond_syscall(sys_timerfd_create);
 cond_syscall(sys_timerfd_settime);
 cond_syscall(sys_timerfd_gettime);