tool/gocross: fix argument order to find

To avoid warning:

    find: warning: you have specified the global option -maxdepth after the argument -type, but global options are not positional, i.e., -maxdepth affects tests specified before it as well as those specified after it.  Please specify global options before other arguments.

Fixes tailscale/corp#23689

Change-Id: I91ee260b295c552c0a029883d5e406733e081478
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f