Fix the unused-parameter in fusion stuff.
Fix the unused-parameter in fusion stuff.

Still not sufficient...

diku-dk/futhark,mrakgr/futhark,HIPERFIT/futhark,diku-dk/futhark,ihc/futhark,CulpaBS/wbBach,diku-dk/futhark,ihc/futhark,diku-dk/futhark,mrakgr/futhark,mrakgr/futhark,HIPERFIT/futhark,ihc/futhark,diku-dk/futhark,HIPERFIT/futhark