tty: Move tty_check_change() helper

Move is_ignored() to drivers/tty/tty_io.c and re-declare in file
scope.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 798acb6..e8996fc 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -381,6 +381,12 @@
 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
 #endif
 
+static int is_ignored(int sig)
+{
+	return (sigismember(&current->blocked, sig) ||
+		current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
+}
+
 /**
  *	tty_check_change	-	check for POSIX terminal changes
  *	@tty: tty to check