[CIFS] Fix SMB2 negotiation support to select only one dialect (based on vers=)

Based on whether the user (on mount command) chooses:

vers=3.0 (for smb3.0 support)
vers=2.1 (for smb2.1 support)
or (with subsequent patch, which will allow SMB2 support)
vers=2.0 (for original smb2.02 dialect support)

send only one dialect at a time during negotiate (we
had been sending a list).

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index a792282f0..2fdbe08 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -272,6 +272,7 @@
 static const match_table_t cifs_smb_version_tokens = {
 	{ Smb_1, SMB1_VERSION_STRING },
 	{ Smb_21, SMB21_VERSION_STRING },
+	{ Smb_30, SMB30_VERSION_STRING },
 };
 
 static int ip_connect(struct TCP_Server_Info *server);
@@ -1074,6 +1075,10 @@
 		vol->ops = &smb21_operations;
 		vol->vals = &smb21_values;
 		break;
+	case Smb_30:
+		vol->ops = &smb21_operations; /* currently identical with 2.1 */
+		vol->vals = &smb30_values;
+		break;
 #endif
 	default:
 		cERROR(1, "Unknown vers= option specified: %s", value);