Merge branch 'mk_eth_soc_fixes-perf-improvements'

Ilya Lipnitskiy says:

====================
mtk_eth_soc: fixes and performance improvements

Most of these changes come from OpenWrt where they have been present and
tested for months.

First three patches are bug fixes. The rest are performance
improvements. The last patch is a cleanup to use the iopoll.h macro for
busy-waiting instead of a custom loop.

v2:
 - Reverse christmas tree in "use iopoll.h macro for DMA init"
 - Use cond_resched() instead of iopoll.h macro in "reduce MDIO bus
   access latency"
 - Use napi_complete_done and rework NAPI callbacks in a new patch
====================

Signed-off-by: David S. Miller <davem@davemloft.net>