bcmgenet_timeout() executes in atomic context, yet we will invoke
napi_disable() which does sleep. Looking back at the changes, disabling
TX napi and re-enabling it is completely useless, since we reclaim all
TX buffers and re-enable interrupts, and wake up the TX queues.

Fixes: 13ea6578 ("net: bcmgenet: improve TX timeout")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>