net/via-rhine: Fix scheduling while atomic bugs

There are BUGs "scheduling while atomic" triggered by the timer
rhine_tx_timeout(). They are caused by calling napi_disable() (with
msleep()). This patch fixes it by moving most of the timer content to
the workqueue function (similarly to other drivers, like tg3), with
spin_lock() changed to BH version.

Additionally, there is spin_lock_irq() moved in rhine_close() to
exclude napi_disable() etc., also tg3's way.

Reported-by: Andrey Rahmatullin <wrar@altlinux.org>
Tested-by: Andrey Rahmatullin <wrar@altlinux.org>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>