n_gsm: Copy n2 over when configuring via ioctl interface

The n2 field is settable but didn't get propogated

Signed-off-by: Ken Mills <ken.k.mills@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 04ef3ef..7f79044 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2375,6 +2375,7 @@
 	gsm->mru = c->mru;
 	gsm->encoding = c->encapsulation;
 	gsm->adaption = c->adaption;
+	gsm->n2 = c->n2;
 
 	if (c->i == 1)
 		gsm->ftype = UIH;