tester: Enable LE Generate DHKey Complete event

This patch adds LE Generate DHKey Complete event for
LE Event Mask list for 'LE Generate DHKey'.
diff --git a/tools/hci-tester.c b/tools/hci-tester.c
index 1e9ce4e..7873e7a 100644
--- a/tools/hci-tester.c
+++ b/tools/hci-tester.c
@@ -550,6 +550,7 @@
 
 	memset(lsem.mask, 0, 8);
 	lsem.mask[0] |= 0x80;	/* LE Read Local P-256 Public Key Complete */
+	lsem.mask[1] |= 0x01;	/* LE Generate DHKey Complete */
 
 	bt_hci_send(user->hci_ut, BT_HCI_CMD_LE_SET_EVENT_MASK,
 					&lsem, sizeof(lsem), NULL, NULL, NULL);