check_software: tolerate libmvec in ldd check

libmvec ( https://sourceware.org/glibc/wiki/libmvec ) is part of
libc.

$ dpkg -S /lib/x86_64-linux-gnu/libmvec-2.24.so
libc6:amd64: /lib/x86_64-linux-gnu/libmvec-2.24.so