[PATCH] r8169: new PCI id

The USR 997902 is based on the 8169 chipset.

The value has been extracted from the sources of the driver which
comes with the manufacturer's cdrom. Heads-up and test by TommyDrum
<mycooc@yahoo.it>.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>