[LEDE-DEV] Generic way to disable Generic Receive Offload (GRO)

[rosenp at gmail.com]

So LEDE is using fq_codel by default. On the cake homepage is this
little sentence:

"Preliminary indications are that not doing GRO “peeling” is where the
first generation of fq_codel enabled 802.11ac routers went wrong in
their QoS systems."

On my Archer C7v2, I've been able to observe that by disabling GRO
using ethtool, I've been able to get a 1-2ms reduction in my overall
latency when browsing the internet.

Anyone know if there is a way to disable GRO without having to install
ethtool?

On a side note, the ethernet driver for the Archer needs some love.
It's not using the correct API for GRO (using netif_receive_skb instead
of napi_gro_receive).