os_freebsd.cpp: fixed #321 (compiler warning on 32 bit architectures)



git-svn-id: https://svn.code.sf.net/p/smartmontools/code/trunk/smartmontools@3902 4ea69e1a-61f1-4043-bf83-b5c94c648137
fix changelog

git-svn-id: https://svn.code.sf.net/p/smartmontools/code/trunk/smartmontools@3903 4ea69e1a-61f1-4043-bf83-b5c94c648137