CORE-V: Fix typo in mac/msu tests

Created by: craigblackmore

gcc/testsuite/ChangeLog:

* gcc.target/riscv/cv-march-xcvmac-test-autogeneration-mac.c: Replace -02 with -O2.
* gcc.target/riscv/cv-march-xcvmac-test-autogeneration-msu.c: Likewise.

The tests pass for me after this change.