more fixes for uint conversions based on latest QEMU patches by Tom Musta

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12124 6c8e4198-a580-4521-a02f-c9ae86df1db9
fixed writing half vector for avx-512

git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12125 6c8e4198-a580-4521-a02f-c9ae86df1db9