Merge branch 'Rework-mt762x-GDM-setup-flow'

MarkLee says:

====================
Rework mt762x GDM setup flow

The mt762x GDM block is mainly used to setup the HW internal
rx path from GMAC to RX DMA engine(PDMA) and the packet
switching engine(PSE) is responsed to do the data forward
following the GDM configuration.

This patch set have three goals :

1. Integrate GDM/PSE setup operations into single function "mtk_gdm_config"

2. Refine the timing of GDM/PSE setup, move it from mtk_hw_init
   to mtk_open

3. Enable GDM GDMA_DROP_ALL mode to drop all packet during the
   stop operation
====================

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