comms/cutecom: Fix WRKSRC name

[jwb]

Summary

comms/cutecom: Fix WRKSRC name
Neglected to retest in poudriere following last-minute PORTNAME change
before previous commit.
Approved by jrm (mentor) or wen (mentor)
Differential to be added to commit message

Test Plan

portlint -AC: looks fine
Passed poudriere on {10.4,11.1}-{amd64,i386}