Bluetooth: smp: Fix possible NULL dereference

smp_chan_create might return NULL so we need to check before
dereferencing smp.

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 16ef0dc..901a616 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -579,8 +579,11 @@
 
 	if (!test_and_set_bit(HCI_CONN_LE_SMP_PEND, &conn->hcon->flags))
 		smp = smp_chan_create(conn);
+	else
+		smp = conn->smp_chan;
 
-	smp = conn->smp_chan;
+	if (!smp)
+		return SMP_UNSPECIFIED;
 
 	smp->preq[0] = SMP_CMD_PAIRING_REQ;
 	memcpy(&smp->preq[1], req, sizeof(*req));