math/cado-nfs: Replace USE_GCC=any with USE_GCC=yes

Since commit 96c17633 in May 2021
USE_GCC=any is just an old (and odd) way of writing USE_GCC=yes and
was deprecated even before. Replace it with USE_GCC=yes.

(Ideally USE_GCC was not necessary at all; ports should be converted
away from it.)