package/glibc: provide an upstream site link

package/glibc: provide an upstream site link

The Config.in for glibc is a blind option and not part of the menu for
a user to select (the pkg is used for the Buildroot toolchain build),
however this patch adds the link for completeness of the pkg-stats
report and for future scripting which will generate xml updates of the
package's Common Product Enumeration (used for vunerability checking).

Signed-off-by: Matt Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>