cifs: Add handling of blank password option

The option to have a blank "pass=" already exists, and with
a password specified both "pass=%s" and "password=%s" are supported.
Also, both blank "user=" and "username=" are supported, making
"password=" the odd man out.

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/connect.c

@@ -186,6 +186,7 @@ static const match_table_t cifs_mount_option_tokens = {
 	{ Opt_user, "user=%s" },
 	{ Opt_user, "username=%s" },
 	{ Opt_blank_pass, "pass=" },
+	{ Opt_blank_pass, "password=" },
 	{ Opt_pass, "pass=%s" },
 	{ Opt_pass, "password=%s" },
 	{ Opt_blank_ip, "ip=" },