cmake: we need link to boost::utf

fix:

/usr/bin/ld: svd.cc:(.text._Z4testILb0ELb1EEvv[_Z4testILb0ELb1EEvv]+0x17cf): undefined reference to `boost::test_tools::tt_detail::report_assertion(boost::test_tools::assertion_result const&, boost::unit_test::lazy_ostream const&, boost::unit_test::basic_cstring<char const>, unsigned long, boost::test_tools::tt_detail::tool_level, boost::test_tools::tt_detail::check_type, unsigned long, ...)'
/usr/bin/ld: CMakeFiles/svd.dir/svd.cc.o:(.data.rel.ro+0x0): undefined reference to `boost::unit_test::lazy_ostream::inst'
collect2: error: ld returned 1 exit status
make[4]: *** [tests/CMakeFiles/svd.dir/build.make:109: tests/svd] Error 1
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