fs: fsconfig: intercept non-new mount API in advance for FSCONFIG_CMD_CREATE_EXCL command

fsconfig with FSCONFIG_CMD_CREATE_EXCL command requires the new mount api,
here we should return -EOPNOTSUPP in advance to avoid extra procedure.

Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Link: https://lore.kernel.org/r/20240522030422.315892-1-lihongbo22@huawei.com


Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>