devel/py-cffi: Update to 1.11.5

While I'm here, remove post-patch target (upstreamed)

Changelog:

https://cffi.readthedocs.io/en/latest/whatsnew.html#v1-11-5

PR: 225111
Submitted by: Henrik Hudson <ports thelanman net> (with changes)
Approved by: portmgr (maintainer timeout, > 2 weeks (1+ months))