Fix small typo in arithmetic
Fix small typo in arithmetic

A case was missed, and it was generating a label
instead of a switch case.

k0gaMSX/scc,8l/scc,8l/scc,k0gaMSX/kcc,k0gaMSX/kcc,8l/scc,k0gaMSX/scc,k0gaMSX/scc