rename avx512_mask.cc

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@11812 6c8e4198-a580-4521-a02f-c9ae86df1db9
fixed makefile after file rename

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@11813 6c8e4198-a580-4521-a02f-c9ae86df1db9