simplify legacy (sse and avx) sad calculation in simd_int.h

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12458 6c8e4198-a580-4521-a02f-c9ae86df1db9
fixed typo in prev checkin

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12459 6c8e4198-a580-4521-a02f-c9ae86df1db9
simplify code a little more

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12460 6c8e4198-a580-4521-a02f-c9ae86df1db9