Bugfixes for fmul rounding

Fix the places I forgot to add Force25Bit, and fix an incredibly silly typo bug
Merge pull request #887 from FioraAeterna/fmulinterp

Bugfixes for fmul rounding
Fix another absent-minded typo in the fmul interpreter patch
Merge pull request #888 from FioraAeterna/fmulinterp

Fix another absent-minded typo in the fmul interpreter patch