fs/smb/client: Reset password pointer to NULL

Forget to reset ctx->password to NULL will lead to bug like double free

Cc: stable@vger.kernel.org
Cc: Willy Tarreau <w@1wt.eu>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Quang Le <quanglex97@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/client/fs_context.c

@@ -1541,6 +1541,7 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
 
  cifs_parse_mount_err:
 	kfree_sensitive(ctx->password);
+	ctx->password = NULL;
 	return -EINVAL;
 }