kernel: load r8169 network module at boot time

kernel: load r8169 network module at boot time

This allows the network interface naming to be stable, free from any
possible interaction from external USB network devices that might
claim usb* interface names.

(This was a real problem I encountered with a nanopi R6S device and
an external rtl8152 usb3 network controller - the USB controller would
claim the eth1 name, causing much confusion).

Signed-off-by: Michel Lespinasse <michel@lespinasse.org>
Link: https://github.com/openwrt/openwrt/pull/17638
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>