BUILD: stats: fix missing '=' sign in array declaration

BUILD: stats: fix missing '=' sign in array declaration

I introduced this mistake when adding the description for the stats
metrics, it's even amazing it built and worked at all! This was
reported by Travis CI on non-GNU platforms :

src/stats.c:92:39: warning: use of GNU 'missing =' extension in designator [-Wgnu-designator]
    [INF_NAME]               { .name = "Name",                        .desc = "Product name" },
                             ^
                             =
No backport is needed.