FRV: Prevent syscall exit tracing and notify_resume at end of kernel exceptions

Move the test for kernel mode processing from do_signal() into entry.S to also
prevent system call exit tracing and userspace resumption notification handling
happening when returning from kernel exceptions.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/frv/kernel/signal.c

@@ -474,18 +474,8 @@ static void do_signal(void)
 {
 	struct k_sigaction ka;
 	siginfo_t info;
-	sigset_t *oldset;
 	int signr;
 
-	/*
-	 * We want the common case to go fast, which
-	 * is why we may in certain cases get here from
-	 * kernel mode. Just return without doing anything
-	 * if so.
-	 */
-	if (!user_mode(__frame))
-		return;
-
 	signr = get_signal_to_deliver(&info, &ka, __frame, NULL);
 	if (signr > 0) {
 		handle_signal(signr, &info, &ka);