signal/signalfd: Add support for SIGSYS

I don't know why signalfd has never grown support for SIGSYS but grow it now.

This corrects an oversight and removes a need for a default in the
switch statement.  Allowing gcc to warn when future members are added
to the enum siginfo_layout, and signalfd does not handle them.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/fs/signalfd.c b/fs/signalfd.c
index 31e9602..f652249 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -134,7 +134,6 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
 		new.ssi_stime  = kinfo->si_stime;
 		break;
 	case SIL_RT:
-	default:
 		/*
 		 * This case catches also the signals queued by sigqueue().
 		 */
@@ -143,6 +142,11 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
 		new.ssi_ptr = (long) kinfo->si_ptr;
 		new.ssi_int = kinfo->si_int;
 		break;
+	case SIL_SYS:
+		new.ssi_call_addr = (long) kinfo->si_call_addr;
+		new.ssi_syscall   = kinfo->si_syscall;
+		new.ssi_arch      = kinfo->si_arch;
+		break;
 	}
 
 	if (copy_to_user(uinfo, &new, sizeof(struct signalfd_siginfo)))