zig cc: fix wrong flag name from earlier commit

In dfe942024461a3598fc872ea79e7859a8744b550, I made a typo. This commit
corrects it. I tested this commit via a patch to zig-bootstrap.
80be5e4832Andrew Kelley committed on 12/6/2022, 7:09:17 AMparent861aa98
1 file changedLine totals unavailable